2020 Spring Meeting
Biomaterials and soft materialsT
Cellulose electronics and photonics: a new challenge for materials a new opportunity for devices
This symposium aims to join the research community working in multifunctional cellulose-based materials posing an innovative vision for new concepts, fundamental understanding, and applications. This includes topics from fibre preparation/functionalization and multi-scale modelling to new devices and processing techniques.
Concerns about sustainability have attracted a great interest in renewable materials from nature as emerging solutions to a range of technological challenges. In particular, cellulose-based materials are not only biocompatible and earth-abundant but also have nature-provided intrinsic structures for potentially transformative impact on new recyclable electronic and photonic devices like paper displays, smart labels, smart packaging, bio-and medical applications, point-of-care (PoC) devices, RFID tags, disposable sensors and actuators, energy harvesting devices, among others.
To enable all these possible applications, some challenges in fundamental research and understanding must be surpassed, which include giving new functionalities to cellulose and structures with tailored properties, novel devices with both proper functionality and mechanical flexibility, cost effectiveness, scalable and reliable manufacturing techniques, and system-level integration.
This symposium aims to gather the research community working with cellulose-based materials and cover recent developments in topics that include: micro/nano fibers functionalization and assembling, new cellulose-based substrates (nanocellulose, bacterial cellulose, etc), nanocomposites with other functional materials (conductors, semiconductor, insulators, piezoelectric/triboelectric, ion-permeable), multi-functional devices and actuators, bio-mimetic/nature-inspired structures, and cost-effective manufacturing technologies on large area (printing and roll-to-roll processes).
Hot topics to be covered by the symposium:
- Cellulose and other related biomaterials such as lignin.
- Nanocellulose-based functional structures and self/hierarchical assembly
- Mechanical/thermal/barrier properties and multi-scale modeling
- Micro/nanofluidics and biosensors on cellulose and related biomaterials
- Electronic devices such as flexible electronics,
- Sensors and actuators
- Plasmonics and nanophotonics,
- Energy harverting applications such as solar cells, batteries, supercapacitors and piezo/triboelectrics
- Other emerging applications such as smart materials, membranes and others
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Overview : Subir Biswas
Authors : Elvira Fortunato
Affiliations : CENIMAT/i3N Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia (FCT-NOVA), Universidade NOVA de Lisboa and CEMOP/UNINOVA, 2829-516 Caparica, Portugal
Resume : We have been observing a rapid and growing interest concerning the utilization of materials of renewable origin for a wide range of applications. One of the most representative example is cellulose, not only in the form of raw material mainly for pulp and paper production, but also in the development of advanced materials/products with tailor-made properties, especially the ones based on nanostructures. Five years ago paper electronics was pure science fiction, but today we have already several paper-based electronics like integrated circuits, supercapacitors, batteries, fuel cells, solar cells, transistors, microwave electronics, digital logic/computation, displays, user interfaces, transparent substrates, substrates with high strength, wearable devices, and new rapid diagnostic tests. These devices with their associated physics and processing will play an important and relevant role to our society special for environmental sustainability, safety, communication, health, and performance. In this talk we will discuss the state of the art and potential future directions in paper-based electronics with special emphasis to the work developed at CENIMAT|i3N, covering electronic devices, smart displays, printed electronics, sensors and rapid diagnostic tests.
Substrates : Elvira Fortunato
Authors : Subir Kumar Biswas, Hiroyuki Yano
Affiliations : Kyoto University, Japan
Resume : Transparent substrates are used in optoelectronic devices, such as photovoltaics, displays, smart windows, touch screens, and so forth. Glass is the conventional choice for the substrate material. However, the recent rapid expansion of light-weight, thin-film, bendable, and wearable consumer optoelectronics demands for flexible and transparent substrates. Plastics are the obvious choice, but they require amelioration in their thermal and mechanical durability. Nanocelluloses, nature’s wonder material, mainly found and extracted from plant cell walls, are perfect reinforcement to improve the thermal and mechanical durability of plastics without jeopardizing their optical transparency and flexibility. This talk will focus on the development of a new technique based on the oil-water interaction of nanocelluloses and resin to obtain a thermally superstable, highly transparent, and flexible nanocomposite substrate having a hierarchical microarchitecture. Additionally, typical challenges associated with the production of nanocellulose-reinforced transparent materials and future directions will also be discussed.
Authors : Rahmatika, A. M.*(1), Kitamura, T.(2), Goi,Y.(2), Morita, Y.(2), & Ogi, T.(1)
Affiliations : (1) Hiroshima University, Japan; DKS Co. Ltd, Japan; *lead presenter
Resume : Effective protein adsorption has attracted attention for broad application in the biomedical field. Cellulose nanofiber (CNF) is a promising material in bottom-up biomedical applications due to its abundance, sustainability, high aspect ratio, biocompatibility, and low toxicity. In this study, CNF with a high density of carboxylate group was used to decorate macroporous particles to demonstrate spontaneous protein adsorption in high capacity. As a result, it possesses a unique CNF network on the macroporous framework with a high-negative charge and successfully increased the specific surface area 10 times higher than that of TOCN particles. These characteristics provide rich sites of electrostatic interaction to exhibit an outstanding rapid adsorption capacity of lysozyme (1865 mg/g) by variating the CNF concentration, and remarkably high reusability (adsorption and released protein) performance after 10 times of use. This unique nanostructure can be an ideal platform for a variety of applications such as drug delivery, protein adsorption, biosensors, and other biomedical fields.
Authors : Dagmawi Belaineh, Valerio Beni, Mats Sandberg
Affiliations : RISE Research Institutes of Sweden, Division ICT, RISE Acreo, 601 17 Norrköping Sweden
Resume : Cellulosic products are sustainable solutions for a range of electronic applications owing to their inherent biocompatibility and molecular structure. One of their common uses is in the field of high-voltage insulation in various machines such transformers. Despite the common use of cellulose in high-field applications there are no quick and simple methods to test the electronic properties of different cellulosic materials in high voltages. This is due to the bulky nature of the test materials that necessitates the application of considerably high voltages (>200 V) for the investigations. In this study, we prepare thin films of cellulose that allow the investigation of the properties of cellulose, such as remnant polarization in cellulose i.e. ferro/piezo-electricity, and breakdown electric fields, using low voltage equipment. We resolve the limited presence of pin-holes in the cellulose films by forming a thin film of high-dielectric interlayer material. We show that it is possible to investigate the effect of high electric fields on cellulosic materials with simple lab equipment and applying low voltages (< 20 V). Using this technique, we study the dependence of the high-filed properties on cellulosic charge and the presence of various counter ions. Furthermore, we are able to investigate the role of humidity and the effect of using higher boiling point solvents in precursor cellulosic solutions.
Authors : T. Tammelin,1 A. Khakalo,1 T. Mäkelä,1 H. Setälä,1 D. Srivastava,2 A. J. Karttunen,2 E. Chavez-Angel,3 M. Kreuzer,3,4 C. Sotomayor Torres,3 J. Ahopelto1*
Affiliations : 1 VTT Technical Research Centre of Finland Ltd, Finland 2 Aalto University, Finland 3 ICN2 - Catalan Institute of Nanoscience and Nanotechnology, Spain 4 Current address: ALBA SYNCHROTRON LIGHT SOURCE, Spain * e-mail: Jouni.email@example.com
Resume : Nanocellulose has been seen merely as fibrous material suitable to improve the surface finish of paper products, in composites and construction materials, as porous material in filters, insulators and aerogels and as scaffolds for tissue engineering, but the potential of the crystalline structure has not been fully considered. The elementary fibrils of nanocellulose are 1-dimensional single crystals with translational symmetry and, consequently, nanocellulose can be seen as a large band gap semiconductor with a band gap of about 5 eV . Nanocellulose is transparent from infrared to ultra-violet down to 230 nm, making it an interesting recyclable candidate for optical applications, even at deep UV. Moreover, nanocellulose can be patterned by nanoimprinting or by casting, i.e., a material suitable for large-scale manufacturing . In this contribution, we will present the optical properties of TEMPO-oxidised nanocellulose and will also discuss the potential to modify the optical properties by binding desired molecules on the cellulose nanocrystals. The recent band structure calculations based on dispersion corrected density functional theory fully support the experimental results .  C. Simao et al., Carbohydrate Polymers 126, (2015) 40.  T. Mäkelä, M. Kainlauri, P. Willberg-Keyriläinen, T. Tammelin and U. Forsström, Microelectronic Engineering 163 (2016) 1-6.  D. Srivastava, M. S. Kuklin, M. Vuorte, M. Sammalkorpi, J. Ahopelto, A. J. Karttunen, to be published.
Authors : Paul Grey, Susete N. Fernandes, Diana Gaspar, Jonas Deuermeier, Rodrigo Martins, Elvira Fortunato, Maria H. Godinho and Luís Pereira
Affiliations : i3N/CENIMAT, NOVA School of Science and Technology (FCT-NOVA), Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
Resume : Mesoporous structures made of cellulose nanocrystals (CNCs) and their self-assembly into films is of great interest not only due to their abundancy and sustainability but also due to their ease of chemical modification and nanoscale bio mimicry capabilities. However, their implementation into (opto)electronic devices requires further understanding on how these self-assembled twisted mesoporous superstructures influence the response of the device to an electrical stimulus. This work focusses on the infiltration of the mesoporous solid structures, with three distinct alkali ions (Li+ , Na+ and K+ ) to yield films with improved electrochemical response when compared to pristine ones, while preserving their photonic character. Electrochemical characterization shows capacitances of up to 2.5 μF cm-2 allowing for their integration as solid-state gate electrolytes in amorphous indium-gallium-zinc-oxide transistors, resulting in low operating voltages (< 2 V), On/Off ratios of up to 6 orders of magnitude and high saturation mobilities >10 cm2 V-1 s-1. Devices fabricated on Na+ and K+ infiltrated CNC films present the best characteristics, indicating pure capacitive charging of the semiconductor. The insights presented here contribute to applications in solid-state ionics in mesoporous structures or the combination of optically active electrolytes capable of providing unique functionalities in ion-gated transistors and circuitry.
Authors : Ana Catarina Trindade1*, Susete Fernandes2, Florian Puchtler3 Josef Breu3, Maria Helena Godinho2, Jon Otto Fossum1
Affiliations : 1 Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway. 2 Departamento de Ciência dos Materiais and CENIMAT/I3N, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, Portugal. 3 Inorganic Chemistry, University of Bayreuth, Germany.
Resume : Solid films prepared from cellulose nano crystals (CNCs) present iridescence and selective reflection of left circularly polarized (LCP) light , while nano clay particles organize as lamellar structures in the solid state. It is well known that aqueous suspensions of sodium fluorohectorite (NaFh) clay biaxial platelets can form a nematic uniaxial liquid crystalline phase . In this work we dissolved different quantities of cellulose nanorods in the clay nematic liquid crystalline suspensions (CNC/NaFh). From this suspensions, thin films by drop-casting method and solid films by solvent evaporation method were prepared. We demonstrate that not only iridescent films can be produced but also their selective reflection of LCP light channel can be induced. For lower concentration of CNCs the films became slightly iridescent with no selective reflection on the left circularly polarized light channel. The colors reflected by the films can vary from blue to red, depending on the amount of CNCs added to the system. Both precursor solutions and photonic films were investigated by means of Fourier Transform Infrared (FTIR), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), Elemental Analysis (EA), Thermogravimetric Analysis (TG-DSC), Small Angle Neutrons Scattering (SANS), Polarized Optical Microscopy (POM) and Scanning Electronic Microscopy (SEM)  S. Fernandes et al. (2017) Adv. Mater., 29, 1603560  Hemmen H. et al. (2012) Rev. Cubana Fisica, 29(1E), 59
Authors : L. Jay Guo, Wei-Jie Feng
Affiliations : Electrical Engineering and Computer Science, Macromolecular Science and Engineering; Macromolecular Science and Engineering
Resume : This work introduces an approach to tune the optical color contrast of cellulose nanocrystal assembled film. Inspired by the iridescent pericarp of natural fruits1 which originates from a cellulose helicoidal cell wall structure, self-assembled cellulose nanocrystal (CNC) chiral structure provides a new way of building photonic material structures at nanoscale to exploit its interactions with light. Owing to the chiral nature of the cellulose chain, CNCs possess a right-handed twist along the long axis with negatively charged surface. These twisted surfaces interact strongly with each other as the CNC concentration increases and finally undergoes a first order phase transition into a chiral nematic phase. Further evaporation of the solvent results in a solid iridescent film with a well-defined helical pitch in the visible wavelength2. However, due to the strong scattering of the nanocrystal, the color of CNC film generally looks pale comparing to the conventional layered structural colors. Here, we adopt a common strategy used to improve the color contrast through the incorporation of light absorbing pigments (i.e. carbon nanotube, polydopamine). Our experiments show that these additives significantly improve the contrast through the suppression of noncoherent light scattering. We also expect these additives would further endow the CNC film with desirable electrical or adhesion property for more practical applications including sensors and adhesives. Conversely, the color could also be tuned towards diffusive white by enhancing the scattering of film with silica nanoparticles. The films with the addition of silica nanoparticle showed a sequential color change from pinkish to white. These methods on color contrast tuning could provide some guidance on the production of more attractive colors that can be realized with the CNC systems in the future. 1. Vignolini, Silvia, et al. "Pointillist structural color in Pollia fruit." Proc. Natl. Acad. Sci. 2012, 109, 15712-15715. 2. Dumanli, Ahu Gumrah, et al. "Controlled, bio‐inspired self‐assembly of cellulose‐based chiral reflectors." Adv. Opt. Mat. 2014, 2, 646-650.
Authors : P.E.S. Silva(1), A.P.C. Almeida(1), Ricardo Chagas(1), S. Fernandes(1), P.L. Almeida(1,2), M.H. Godinho(1)
Affiliations : (1) i3N/CENIMAT, Department of Materials Science, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal (2) Área Departamental de Física, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisboa, Portugal
Resume : Structures with helical shape are commonly found in nature at many scales, ranging from plant tendrils to molecules. Many organisms take advantage of the helical shape to fold, propel and assemble in a “smart” way. For instance, seeds of Erodium use a peculiar mechanism to seed dispersal. Seeds have the capability of drilling in the ground by undertaking several cycles of winding and unwinding. In animals, the cuticula of some beetles exhibits an iridescent cholesteric structure with a selective reflection of left circularly polarised light and transmission of right circularly polarised light. Inspired by how helicity arises in nature, we investigated the mechanisms ruling the shaping of structures, which can find potential applications in micro and nanorobotics, soft-electronics and nanophotonics. Acknowledgements: This work is funded by FEDER funds through the COMPETE 2020 Program, National Funds through FCT - Portuguese Foundation for Science and Technology and POR Lisboa2020, under the projects numbers POCI- 01-0145-FEDER-007688 (Reference UID/CTM/50025), UID/BIA/00329/2013, PTDC/CTM-BIO/6178/2014, M-ERA-NET2/0007/2016 (CellColor) and PTDC/CTM-REF/30529/2017 (NanoCell2SEC). References:  P. E. S. Silva, F. V. de Abreu, M. H. Godinho. Soft Matter, 13(38), 6678-6688 (2017).  A. P. C. et al. Soft Matter, 15, 2838-2847 (2019).  S. N. Fernandes et al. Advanced Materials, 29(2), 1603560 (2017).
Authors : R. Chagas1, P.E.S. Silva1, S. Fernandes1, M.H. Godinho1
Affiliations : 1 - i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
Resume : The evolution of living structural colours is quite spectacular and occurs slowly over time. For example, the eyespots of male peacock feathers present different iridescent colours that evolve from infancy to adulthood. The time needed for the complete eyespot pattern formation is about three years . In this work, we revisit a cholesteric lyotropic cellulosic system  in the presence of a reactive solvent. The solutions show vivid iridescent colours for a given range of concentrations, at room temperature, that change in time. The system was investigated with spectroscopy, using circularly and linearly polarised light, coupled with a polarised optical microscope and scanning electron microscopy. To reduce the time of molecular diffusion the lyotropic solutions, the solutions were confined in capillaries and the development of the vivid cholesteric colours studied in time. The obtained results are consistent with a reaction-diffusion mechanism of the reactive solvent in the presence of the cellulosic chains . Finding the precise mechanism of colour sequence and evolution in time of cellulosic lyotropic solutions has significant implications for future optical/sensor applications. Acknowledgements: This work is funded by FEDER funds through the COMPETE 2020 Program, National Funds through FCT and POR Lisboa2020, under the projects POCI- 01-0145-FEDER-007688(Reference UID/CTM/50025), UID/BIA/00329/2013, PTDC/CTM-BIO/6178/2014, M-ERA-NET2/0007/2016(CellColor) and PTDC/CTM-REF/30529/2017(NanoCell2SEC). References:  M. Mishra, Current Science, 107(2), 186-188 (2014).  A. M. Ritcey, K. R. Holme, D. G. Gray, Macromolecules, 21, 2914-2917 (1988).  A.M. Turing, Philos. Trans. R. Soc. Lond. Ser. B Biol. Sci., 237, 37-72 (1952).
Authors : Kazi M. Alam, Pawan Kumar, Sergey Gusarov, Alexander E. Kobryn, Aarat P. Kalra, Sheng Zeng, Karthik Shankar
Affiliations : Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 1H9, CANADA; Nanotechnology Research Centre, National Research Council Canada, 11421 Saskatchewan Dr, Edmonton, AB T6G 2M9, CANADA;
Resume : We report the fabrication and characterization of highly functional cellulose nanocrystals (CNCs) formed by conjugating metallophthalocyanines (MPcs) to two different types of CNCs -negatively charged CNCs produced by concentrated sulfuric acid hydrolysis of wood pulp and CNCs partially neutralized by NaOH treatment i.e. sodiated CNCs. An esterification protocol was employed to covalently bind carboxylated MPcs to surface hydroxyl group rich CNCs. Detailed physicochemical characterization was performed through FESEM, HRTEM, DLS, XRD, Raman spectroscopy, XPS, NMR, UV-Vis and PL spectroscopy. The bonding and electronic structure in CNC@MPc was investigated using density functional theory (DFT) modelling. Kelvin probe force microscopy (KPFM) measurements of the surface potential before and after illumination indicated photogenerated charge separation in the MPc-conjugated CNCs. This surprising result arose due to the delocalization of photogenerated positive charge in MPc over the negative charged surface of CNCs. The changes in the surface potential measurements for the pristine and functionalized CNCs, using KPFM were in harmony with the spatial molecular orbital localization, as revealed from DFT calculations. DFT calculations also confirmed stable covalent bonding between MPc and CNC. MPc-conjugated CNCs showed highly promising performance in solar fuel production under visible light, and as a sensor for VOCs.
Poster Session : Luis Pereira, Aaron Mazzeo
Authors : Sunita Mehta
Affiliations : CSIR CSIO Chandigarh, Chandigarh, India
Resume : Bio-integrated electronics (BIE) has the potential to revolutionize the healthcare diagnostics and treatments far beyond the current ambulatory clinical technologies. These BIE devices are designed to conform closely to the irregular shape of the human skin and provides the opportunity of monitoring even while performing daily routine activities and are imperceptible to the user. Here we report the development of a BIE device for monitoring physiological mechano-acoustic signals. A highly sensitive accelerometer along with all the necessary components is embedded into the flexible packaging capable of being easily adhering to the skin. Programmable bluetooth chip incorporated into the device allows the data to be processed remotely through a mobile phone. The device thus fabricated has been used for monitoring stroke patients for their talking capability, respiration rate and swallowing ability. The compactness, durability and remote accessibility make this device a ground-breaking development in the field of healthcare. We also report a flexible and wireless implantable device for stimulating the ion-sensitive channels in the brain of genetically modified mouse. The device combines subdermal magnetic coil antennas connected to microscale, injectable lightemitting diodes (LEDs), with ability to operate at wavelengths ranging from UV to blue, green-yellow, and red. This device has been used for understanding and controlling the brain functions in a highly targeted and controlled fashion. Flexible, wireless and fully implantable optoelectronic technology reported here have broad applicability to study the structural and functional relationships in the brain which can play an important role in the healing of neurological diseases.
Authors : Melih Ogeday Cicek(1), Doga Doganay(1,2), Mete Batuhan Durukan(1), Merve Nur Guven(2) and Husnu Emrah Unalan(1,2)
Affiliations : (1) Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800, Ankara, TURKEY (2) Nanovatif Materials Technologies, ODTU TEKNOKENT, 06800, Ankara, TURKEY
Resume : Human-machine interface (HMI) is an important field that certainly necessitate further exploration to enable active communication between man and electronic devices. Touch screens, that can be counted as one of the most crucial HMI devices, are widely used in daily life. However, patterning numerous electrodes to sense and locate human touch is complicated, time consuming and a relatively costly process. Here, a self-powered, pixel-free tactile touch sensor is reported using elastomer – silver nanowire nanocomposites and copper electrodes without the utilization of any electrode arrays. Self-powered, pixel-free tactile sensors can sense position of the touch by the change of voltage output that is created by triboelectrification between human skin and elastomeric surfaces. Such a triboelectric sensing system gives fast and accurate results of touching actions without pressure dependence. A wearable touch keypad is demonstrated by the fabrication of a single array of self-powered pixel-free tactile sensors. The proposed self-powered, pixel-free tactile sensors are highly promising to complement electronic devices such as HMI systems, electronic skins, wearable electronics and soft robotics.
Authors : Manni Yang, Kwang-leong Choy
Affiliations : University College London
Resume : Different from normal wounds, chronic wounds often have a large and deep wound area and patients often experience long-term suffering from inflammation and bacterial infection. In chronic wounds healing process, pH is a key parameter, indicating the state of bacterial infections. For a healthy skin, the typical pH is 5.5-6.5, while in chronic wounds, the pH can be above 8 due to the by-products created by bacteria in the process of cell proliferation. In order to treat wound promptly and effectively, pH monitoring requires multiple measurements from the wound area with high spatial resolutions. However, current wound sensors are mostly in solid forms and cannot detect in different depth of wound area comprehensively, while some flexible sensors are costly and with some chemical-based fabrication methods or materials that could be potentially harmful in human body. Herein we proposed an eco-friendly fabrication of, flexible and highly sensitive pH sensor based on bio-derived material bacterial cellulose for chronic wounds based on bio-derived materials. The resulting composite sensor has near Nernst limit pH sensitivity in the pH range from 4-10, with low Young’s modulus, and also has a long-term sensitivity lasting for at least 24 hours. This renders its applications in flexible bio-sensors and smart wound dressings.
Authors : N. H. Alvi, S. Sardar, X. Crispin, M. P. Jonsson
Affiliations : RISE Research Institute of Sweden, Sandgatan 31, SE-60174 Norrköping Sweden. Laboratory of Organic Electronics, ITN, Linköping University, SE-60174 Norrköping Sweden.
Resume : These days cellulose paper is ubiquitous in our daily life. Cellulose, the major component of paper, can be obtained from plants and represents one of the most abundant organic materials on earth. Cellulose by itself is usually limited in functionalities. Recently, research on organic/inorganic cellulose composites has increased dramatically due to the potential applications in electronics, biosensors, and energy storage devices. The integration of functional micro and nanostructures into the paper, such as zinc oxide tetrapods or nanoparticle powders, has opened up many opportunities for applications in advanced energy harvesting systems and electronic devices. In this respect, one the major challenges is to avoid leakage of the micro- and nanoparticles from the paper over time. This is a serious problem that is limiting their applications into the practical devices. In this work, we present a novel, environmentally friendly and fully scalable approach enabling the production of highly stable paper functionalized with zinc oxide nanostructures. Small (0.5 cm2) two-probe interdigitated carbon electrodes are printed on the paper to form a complete electronic device. It exhibits excellent photosensing properties over a wide range of light irradiances (0.01-1 Sun), with excellent long-term stability. At a bias voltage of 1V, the device shows a strong and repeatable 65 µA photocurrent signal under simulated sunlight. This is more than 100 and 10,000 times better than the photocurrent of our control samples fabricated using zinc oxide tetrapods and nanoparticles, respectively. In addition to the superior photoconductive properties, our paper is smooth and mechanically strong, allowing its applications in a range of ﬂexible energy and electronics devices.
Authors : Sihui Liu
Affiliations : Fenech Salerno. Benji, Tian Carey, Felice Torrisi
Resume : Currently, point-of-care(POC) tests, using devices offering fast and accurate diagnosis has been developed to treat patients.These tests rely on the mature biosensor technical with selectivity and quick responding. For their better performance, the future direction of biosensors’ development major on low-cost, easy-to-use, and high performance.1 A printed FET biosensor will be able to make these come true. The aim of the project is the development of an inkjet-printed FET biosensor with controlled channel properties like electron mobility and conductivity, sheet resistance, contact resistance, and channel morphology. Device manufacturing should be achieved through inkjet-printed devices on a PET substrate. Graphene materials will be used to overcome the limitations of current printed biosensors like the low conductivity and low electron mobilities in the channel. Depending on its capacity, reduced graphene ink might be used instead of pristine graphene ink for better performance. Combining the devices with several biomarkers, the new inkjet-printed sensors should establish their sensitivity and specificity, open a route to multiplexed sensors and eventual point-of-care application of the sensors in early diagnosis of Alzheimer’s disease. Besides its potential application as a biosensor, this graphene device may also find applications within other fields as a wearable sensor.
Authors : Hoik Lee1, Myungwoong Kim2
Affiliations : 1 Research Institute of Industrial Technology Convergence, Smart Textiles R&D Groups, Korea Institute of Industrial Technology, Ansan, 15588, Korea.; 2 Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Korea
Resume : We demonstrate effective functionalization chemistry for cellulose nanofiber modification using thiol functionality. Electrospun cellulose acetate nanofibers were deacetylated to obtain cellulose nanofibers, which were modified further to incorporate thiol on their surface by the esterification of hydroxyl groups with 3,3’-dithiodipropionic acid and further reductive cleavage of the disulfide bond. The thiol functionality was highly versatile to bring simple and efficient chemical reactions to attain (i) Ag nanoparticle-adsorbed cellulose nanofibers by Ag ion reduction at surface, (ii) various amine (primary amine and quaternary amine) functionalized cellulose nanofibers by Michael addition, and (iii) complex polymer functionalized cellulose nanofibers by a radical-based thiol-ene reaction, under mild conditions, i.e. in any reaction media, at room temperature, and under ambient atmosphere, evidenced by a variety of characterization methods including a quantitative analysis with X-ray photoemission spectroscopy. These scalable thiol-based chemistries should offer a new generation of ecofriendly and well-tailored cellulose nanofiber materials with complex inorganic, organic, and polymeric functionalities, potentially expanding to functionalized surfaces of other carbohydrate-based materials to achieve the desired properties.
Authors : Kanika Arora, Kulwinder Kaur and Mukesh Kumar
Affiliations : Functional and Renewable Energy Materials Laboratory, Indian Institute of Technology Ropar, Punjab
Resume : This work introduces a self-powered, highly flexible and high performance paper based solar blind (UVC) photodetector for cost-effective flexible electronic devices. Different from traditional design which involves sophisticated techniques for electrode deposition, we report a facile bottom electrodes. Our proposed structure of amorphous Ga2O3 based UVC photodetector on paper, constituting bottom electrodes, highly boosts the device performance and approaches the lower limit of dark current (1.2 pA). Moreover, bottom electrodes also offer minimum reflectivity and high photogenerated charge carrier separation leading to high On/Off ratio of 104. The proposed bond Eco-friendly all-purpose paper based UVC photodetector exhibits a high responsivity (3.1 mA/W), high detectivity (1.42×1011 jones), high efficiency (1.52%) and quick decay (386 ms) at zero bias. Apart from that, a rigorous flexibility test showed remarkable sustainability at high bending curvatures (30 cm-1) and even for large twisting angles (±180o). Paper substrate well supported the electrodes imbibed into its micro-fibrous structure, offering excellent stability and ultrahigh flexibility. Highly stable bottom electrodes are considered to be the root cause of exceptionally stable operation (3000 hrs), much enhanced performance and high tolerance of the device even towards higher biases upto 100 V. Figure of merits of the reported device has largely surpassed the previously reported devices based on non-flexible expensive substrates. Development of such photodetector is a great step towards “internet of things” wearable and economically viable mass electronics to monitor potentially dangerous deep-UV (DUV) signal.
Authors : Hoseong Song, Sooman Lim
Affiliations : "Graduate School of Flexible and Printable Electronics, Jeonbuk National University, Jeonju, Republic of Korea" "LANL-JBNU Engineering Institute, Jeonju, Republic of Korea"
Resume : In this work, we demonstrate the facile preparation of photopolymerized polyvinylidene fluoride (PVDF) composite film via digital light processing (DLP) UV light irradiation based three-dimensional (3D) printing technique. The 3D printed PVDF film was in-situ polled for 10 hours to obtain β-phase in the PVDF structure which exhibits prominent piezoelectric properties. The PVDF based piezoelectric sensor prepared via 3D printing recorded a piezoresponse of 400 mV at a film thickness of 0.5 mm, which is 2.7 times higher than that (~150 mV) of the counterpart prepared via conventional technique. Additionally, the bending test results also confirmed that the 3D printed piezoelectric sensor has high mechanical flexibility and durability. Most importantly, the entire device fabrication process using the one-step 3D printing technique is approximately 10 times faster than the conventional process. Upon optimization, the cost-efficient 3D printing with in-situ polling method introduced herein could potentially be the key to the mass production of piezoelectric sensor in the near future. KEYWORDS: 3D printing, piezoelectric, polyvinylidene fluoride, sensors, additive manufacturing, DLP(digital light processing)
Authors : Alexandre Fonseca, Paul Grey, Diana Gaspar, Rodrigo Martins, Elvira Fortunato and Luis Pereira
Affiliations : Departamento de Ciência dos Materiais, i3N/CENIMAT, NOVA School of Science and Technology (FCT-NOVA), Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
Resume : The natural ability of Cellulose Nanocrystals (CNCs) to self-organize into a chiral nematic liquid crystal phase with a helical arrangement that can be retained in dry CNC films, gives iridescent colors and interesting photonic properties. These properties include selective reflection and transmission of right- and left-handed circular polarized light (RCPL and LCPL, respectively). Many techniques for the production of such films, particularly drop-casting, have already been explored. Due to the rods’ negative zeta potential, owing from the acidic hydrolysis synthesis of the CNCs, electrophoretic deposition presents a viable method to obtain photonic CNC films on larger areas, when compared to conventional methods. The obtained films show the characteristic iridescence, with differences above 50% between transmission in RCPL and LCPL, inside the photonic band gap. Furthermore, structures with the ability to reflect in both, LCPL and RCPL channels, were studied, by using different birefringent materials as retardation plates. With this approach a great variety of colors in LCPL and RCPL can be obtained, depending on the used number of layers and initial photonic bandgap conditions. Stress induced birefringence in different materials was analyzed and the Pockels effect is suggested for future studies, where devices in the area of sensing or information processing can be envisioned.
Authors : Elena Palmieri*(1), Giuseppina Polino(2), Emanuela Tamburri(1), Silvia Orlanducci.(1), Francesca Brunetti (2).
Affiliations : (1) Department of chemical science and technology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy; (2) CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy * lead presenter
Resume : In response to the request for flexible and sustainable energy storage devices with high electrochemical performance, a great interest is focused on developing environmentally friendly supercapacitors. Particularly, there has been growing interest in using paper or paper-like substrates for batteries and other energy storage devices . In this work, a scalable, low cost and easy to process approach for the preparation of printable paper-based energy storage devices is proposed. Large area techniques such as spray coating for the fabrications of the electrodes and blade coating for the deposition of electrolytic separator, were used. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was employed to realize anode and cathode electrodes. The novelty of this work consists in the use of hydroxypropyl cellulose (HPC) charged with detonation nano-diamonds (DNDs) as solid electrolyte itself or added with a sodium sulphate water solution. In order to develop a green solvent free methodology to prepare devices, all components were chosen or formulated in water-based dispersions. The performance obtained using solid electrolyte (HPC+DNDs) and electrolyte solution (HPC+DNDs+Na2SO4) are comparable in terms of specific capacitance, with power density in the range of ~16 ÷ 30 µW cm-2.  Brunetti et al, Adv. Funct. Mater. 2019, 1806798
Authors : Martin Reimer¹, Kai Mayer², Thomas Scheibel², Cordt Zollfrank¹
Affiliations : ¹Technical University of Munich - Campus Straubing for biotechnology and sustainability (TUMCS), Professorship for Biogenic Polymers, Schulgasse 16, 94315 Straubing, Germany. ²University of Bayreuth, Biomaterials, Prof-Rüdiger-Bormann-Str. 1, 95447 Bayreuth, Germany.
Resume : In this study a biological polymer optical fiber was produced sustainably under moderate conditions and can be ecologically recycled after use, or be biograded. A colorless solution of cellulose in DMAc/LiCl was prepared. The created solution was used to build the core of the light guider by a wet-spinning process into ethanol. Recombinantly produced spider silk proteins were used as the cladding material. The proteins were dissolved in HFIP and added dropwise to the core. The silk was treated with 70 % ethanol as liquid or vapor to become water-insoluble. The chemical and optical properties of the regenerated cellulose and the silk proteins were studied from cast films using Fourier-transform infrared spectroscopy and ultraviolet-visible measurements. In the visible range of the spectrum, the regenerated cellulose achieves a transmission of 90-91 % with a refractive index of 1,575. The post treatments of the silk proteins promotes the absorption in the ultraviolet range. In the visible range, all silk samples form highly transparent materials. The post treatments increases the refractive index of the silk. The attenuation constant of the fibers was determined by substituation method in the range between 535 nm and 985 nm. The pure cellulose has a minimum of 6,0 dB/cm at 893 nm. Due the covering of the cellulose fiber with the differently treated silks, the attenuation constant of the polymer optical fibers decreases in the area and reaches a minimum value of 2,8-2,9 dB/cm. Acknowledgements: This work is supported by the Bavarian State Ministry of the Environment and Consumer Protection.
Authors : Nadezda Prochukhan, Michael A. Morris
Affiliations : School of Chemistry, AMBER, Trinity College Dublin, Ireland
Resume : Fabrication of biopolymer based membranes is an important aspect of the move towards sustainable bioeconomy. Membranes provide a facile method for separation of waste, water purification, bioseparation and various other applications . We report on fabrication of lignin based membranes with various pore sizes and architecture. Lignin is a by-product of the paper and pulp industry, thus it would be beneficial to use lignin for membrane manufacturing. Typically, due to its branched structure and physical rigidity pure lignin membranes are inherently brittle. Thus, we propose facile methods of lignin nanomembrane production as well as scalable lignin composite membrane fabrication such as lignin-zein or lignin-guar membranes. Pure lignin membranes were fabricated via spincoating onto silicon wafer substrates. Resultant lignin nanomembrane morphology is controlled by thermal and solvent vapour annealing. Combination of lignin with elastic biopolymers such as guar gum or zein yields scalable membranes. Those composite membranes were produced via casting from solvent mixtures under controlled temperature and humidity environments in a membrane casting apparatus.  T. Ghoshal, J. D. Holmes and M. A. Morris, Sci. Rep., 8 (2018) 7252.
Authors : Thaynã Ferreira de Souza (1), Debora T. Balogh (2), Antonio J. F. Carvalho* (1)
Affiliations : (1) São Carlos School of Engineering, University of São Paulo (EESC/USP), Brazil; (2) São Carlos Institute of Physics, University of São Paulo (IFSC/USP), Brazil.
Resume : Conductive nanopapers produced with nanofibrilated cellulose (NFC) are of great interest in cellulose electronics (1) since it can be used to produce conductive substrates, tracks and devices with the unique characteristics of NFC (2, 3). Here we describe the preparation and characterization of conductive NFC suspensions and their nanopapers. The conductive NFC were prepared by the polymerization of 3,4-ethylenedioxythiophene containing poly(styrene sulfonic acid) (PEDOT:PSS) (4) in an aqueous suspension of NFC using ammonium perssulfate as initiator. The nanopapers were prepared by casting and dried at 50 oC in a forced air oven. The nanopapers were characterized by FTIR-ATR, SEM, TGA, contact angle and conductivity measurements. The morphological characterization shows very compact and homogeneous nanopapers. FTIR evidences the presence of both main components and conductive measurements shows that the conductivity is dependent on the NFC:PEDOT:PSS proportion. The results obtained up to now shows a very promising system for use in organic electronics. References: (1) Agate, S. et al., Carbohydr. Polym., 198, 249, 2018. (2) Carvalho, A.J.F., J. Renew. Mater. 2, 118, 2014. (3) Tkalya, E. et al., ACS Macro Letters, 2, 157, 2013. (4) Elschner, A. et al. PEDOT- Principles and applications of an intrinsically conductive polymer – CRC Press, 2011. Acknowledgments: AJFC thanks to CNPq proc. # 307124/2015-0 and 303847/2019-0 for its financial support.
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|08:45||PLENARY SESSION 1|
Sensors and actuators : Anna Laromaine
Authors : Wadood Y. Hamad
Affiliations : FPInnovations and University of British Columbia
Resume : Cellulose nanocrystals (CNCs) are lyotropic colloidal liquid crystals (LCs). They can easily be obtained from wood and other biomass, and typically have dimensions of 5-10 nm × 100-500 nm. When prepared with sulfuric acid, the CNCs are modified with sulfate half-ester groups that impart a surface charge and enable them to form stable colloidal suspensions in water. Owing to the large aspect ratio and inherent chirality of the CNCs, they can spontaneously form left-handed chiral nematic LC structures at low concentrations (~4 wt.%). Chiral nematic liquid crystals (CNLCs), also known as cholesteric LCs, are important for displays and other applications owing to their periodic helical structures. Responsive photonic crystals have potential applications in mechanical sensors and soft displays; however, new materials are constantly desired to provide new innovations and improve on existing technologies. To address this, we have developed a suite of scientific solutions based on the actuating and piezoelectric responses of CNCs and stretchable CNC-polymer nanocomposite systems. For instance, stretchable chiral nematic cellulose nanocrystal (CNC) elastomer composites can be prepared to exhibit reversible visible colour upon the application of mechanical stress. When stretched (or compressed) the colourless materials maintain their chiral nematic structure but the helical pitch is reduced into the visible region, resulting in coloration of the CNC-elastomer composite. By increasing the percentage elongation of the material (ca. 50–300%), the structural colour can be tuned from red to blue. Moreover, CNC-polymer nanocomposite films can be prepared in a straightforward manner to produce cost-effective stretchable piezoelectric materials (d33>50 pC/N) that outperform PVDF and some ceramics. We have meticulously documented the structure-property interrelations influencing these responses, and have examined concentration, pH, ionic strength, and electromagnetic field effects. Our presentation will detail these fundamental criteria and how they influence performance and functionality in select end-use application platforms.
Authors : Milad Asadi Miankafshe, Shayan Mehraeen, Jose G. Martinez, Tariq Bashir, Edwin W. H.Jager, Nils-Krister Persson
Affiliations : Milad Asadi Miankafshe; Tariq Bashir; Nils-Krister Persson; Swedish School of Textiles, Smart Textiles, Polymeric E-textiles, University of Borås, S-501 90 Borås, Sweden. Tariq Bashir; Swedish Centre for Resource Recovery, University of Borås, S-501 90 Borås, Sweden. Shayan Mehraeen; Jose G. Martinez; Edwin W. H.Jager; Bionics and Transduction Science, Div. Sensor and Actuator Systems, Department of Physics, Chemistry and Biology (IFM), Linköping University, S-581 83 Linköping, Sweden.
Resume : Developing a cellulosic fibre-based actuator opens up for new fields of cellulosic materials with added value and new types of applications. Being cellulosic potentially offers biodegradability and sustainability as well as low costs of any products. In addition, being textile leads to compatibility with the human body and pliability. Textiles can be transformed into actuators, where the textile construction enables guidance of the actuation direction and amplification of stress and strain. We have selected a regenerated cellulosic fiber (Lyocell) as the main substrate. Fibers were functionalized with nitrate functional groups and then electrostatic grafting of PEDOT:PSS onto cellulose nitrate fibers took place by a dip-coating method to provide electrical conductivity. PEDOT:PSS solution was modified with D-sorbitol and a non-ionic polyurethane-based thickener. Next, polypyrrole (PPy) was electro-synthesised to form a yarn actuator. Further, the impact of optimization of PEDOT:PSS solution, and the role of textile structures in the actuation mechanism, was studied. Using this, we achieved a highly stable conductive electrode coating. Optimization of PEDOT:PSS coating not only increased the conductivity of the E-textile (up to 75%) but also gives a stable electrochemical synthesis of PPy. As a result, the common large electrical conductivity drop during the redox reaction is prevented. We also studied the actuation mechanism of textile structures made. It was observed that the efficiency of actuation highly relies upon the fabric structure and its topology.
Authors : Jesper Edberg*(1), Robert Brooke(1), Omid Hosseinaei(2), Andreas Fall(2), Kosala Wijeratne(1) Mats Sandberg(1)
Affiliations : 1: RISE Acreo Printed Electronics, Bredgatan 35, 602 21 Norrköping, Sweden 2: RISE Bioeconomy, Drottning Kristinas väg 61, 114 28 Stockholm, Sweden * Correspondence: firstname.lastname@example.org
Resume : Laser induced graphene/graphite (LIG) is a method of converting a carbon rich precursor into highly conductive graphene using a laser. This method has shown great promise as a versatile and low-cost patterning technique. Here we show for the first time how an ink based on cellulose and lignin can be patterned using screen printing followed by laser graphitization. Screen printing is one of the most commonly used manufacturing techniques in printed electronics, making this approach compatible with existing processing of various devices. The use of forest-based materials opens the possibility of producing green and sustainable electronics and pre-patterning of the ink precursor enables carbon patterns without residual precursor between the patterns. We investigated the effect of the ink composition, laser parameters and additives on the conductivity and structure of the resulting carbon and could achieve record low sheet resistance of 3.8 Ω/sq and a surprisingly high degree of graphitization. We demonstrated that the process is compatible with printed electronics and finally manufactured a humidity sensor which uses lignin as the sensing layer and graphitized lignin as the electrodes.
Authors : *Sudeshna Mondal and Chandramouli Subramaniam
Affiliations : Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
Resume : Wearable sensors with a non-invasive platform have garnered significant interest over the recent years in the area of personalised healthcare monitoring. Extensive research is being carried out in this field as it utilises recent technology for the fabrication of smart sensors which aims in addressing the demands of epidermal sensing where durability, lightweight, and intimated skin conformance are core requirements. Yet, further progress in this area has been hindered due to the lack of efficient chemical sensors and biosensors, able to monitor the chemical constituents residing on the epidermis of the wearer’s body. In this context, electrochemical sensors offer promise as wearable chemical sensors due to their high performance, inherent miniaturization and low cost. A wide range of electrochemical sensors and biosensors have been developed for real-time non-invasive monitoring of electrolytes and metabolites in sweat, tears, saliva as indicator of wearer’s health status. Substantial progress in this field of electrochemical sensors has led to the development of commercial hand analysers such as ACCU-CHECK (Roche Diagnostics, Inc.), iSTAT (Abbot, Inc.), or Lactate Scout (Sports Resource Group, Inc.), for detecting metabolites and electrolytes. The present work demonstrates the fabrication and characterization of a wearable sensor which can help in real-time, non-invasive monitoring of metal ion levels (K+, Zn2+) in perspiration directly from human epidermis. Potassium, one of the major constituents in sweat after sodium is important for the normal functioning of the human body in regulating blood pressure, normal water balance, muscle contractions and maintain pH balance of the body. It is also an important electrolyte present in the human body. Deficiency in potassium can lead to high blood pressure, muscle paralysis, breathing problems, irregular heart rhythms and constipation. Zinc, another metal present in trace levels in human perspiration; is a primary biomarker for muscular stress and fatigue. It is an important trace metal ion as it is involved in functioning of biochemical processes relevant to enzymes, hormones, and transcription related factors. Perspiration represents an efficient pathway for the release of potassium and zinc which leads to its deficiency in the body. Thus, monitoring of these metal ions in the body from perspiration becomes essential for athletes and for persons engaged in strenuous physical activity for the detection of wide ranging physiological states. Changes of potassium concentration in perspiration beyond optimal concentration (0.2 g/l) and zinc (1.56 µg/ml) can be used as indicators for physiological state of human body, such as low blood pressure and muscular stress and fatigue. While identifying the loss of these metal ions during physical activity is very important, currently very few tools exist for real-time detection of metal ion levels in perspiration. Electrochemical techniques such as stripping voltammetry have also been employed extensively for qualitative and quantitative detection of metal ions from the body. In-situ measurements have been demonstrated using micro-fabricated three-electrode assemblies utilizing expensive and laborious lithographic techniques. Although miniaturized and portable, such systems are not reusable and therefore are expensive and not scalable. Besides, their integration for real-time monitoring has been a challenge. Thus, the need of the hour is a detection system that combines ease of handling, real-time, in-situ analysis and specific detection of these metal ions in perspiration without compromising on the sensitivity reusability and cost-effectiveness; thus paving the way for “Smart” diagnostics. In order to achieve this, we have utilized novel molecular nanomaterials as transducers onto which the ion-selective receptors were immobilized. Specifically, the detection assembly consisted of cellulose fibres that were conformally coated with single wall carbon nanotubes (SWNTs). This resulted in a synergistic relation with the cellulose matrix providing the porosity and SWNTs providing the high specific surface area and electrical conduction pathway for signal transduction resulting in the fabrication of CNT-thread. Achieving ultrahigh sensitivity over a wide concentration range of analyte has been a persistent, mutually exclusive challenge for real-time analytical detection and diagnostics. To this end, we demonstrate a miniaturized, coaxial, cable-type electrochemical sensor comprised of a carbon nanotube immobilized cellulose yarn (CNT-thread) to achieve ultrahigh sensitivity (<1 ppm) across a wide dynamic range (0.1−500 ppm) for the rapid (∼60 s) detection of K+ and Zn2+. The sensor comprises of two cables of CNT-thread, one coated with a polymeric, ion-receptor (tetrakis(p-aminophenyl) porphyrin for Zn2+) and Valinomycin for K+ acting as the working electrode and the other being a reference electrode of pristine CNT-thread. The sensor is extremely tolerant to interference (selectivity coefficient 10−3−10−5) from a wide range of cations (Na+, Mg2+, Cd2+, Ca2+, Fe2+, and Cu2+) and anions (Cl−, NO3−, PO43−, and CH3COO−) enabling real-time detection of K+ and Zn2+. Importantly, excellent signal consistency (<5% deviation) across multiple electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, and chronoamperometry is demonstrated. Minimal deviation (<6%) between the analyte concentrations estimated from the sensor and those estimated from atomic-absorption techniques is observed. Finally, the lifetime and mechanical sturdiness of the sensing platform is illustrated through elaborate experiments involving bending and seamless interfacing with human skin for non-invasive point-of-care analysis. Thus, this portable electrochemical platform enables the real-time analysis of metal ions in human perspiration without compromising on its sensitivity, reusability and cost-effectiveness. References  Bariya, Mallika., Nyein, Y.Y Hnin., Javey, Ali., Nature Electronics 2018, 162 , 160–171.  Heikenfeld, J. Nature 2016, 529, 475–476.  Mondal, S., Subramaniam, C., ACS Sustainable Chem. Eng. 2019, 7, 17, 14569-14579.
Authors : Eero Kontturi, Panagiotis Spiliopouls, Marie Gestranius, Giovanni Marin, Ghiyasi Ramin, Tekla Tammelin, Maarit Karppinen
Affiliations : Eero Kontturi, Panagiotis Spiliopoulos Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, Finland Marie Gestranius, Tekla Tammelin VTT Technical Research Centre of Finland Giovanni Marin, Ghiyasi Ramin, Maarit Karppinen Department of Chemistry and Materials, School of Chemical Engineering, Aalto University, Finland
Resume : Increased energy demands have triggered efforts to explore new routes for fabricating energy efficient materials that combine efficient performance and environmentally friendly operation. Thermoelectric materials are promising candidates in this realm as they are able to transform waste heat into energy via a process involving zero emissions. Good thermoelectric performance requires good electrical conductivity coupled with low thermal conductivity. Current thermoelectric materials involve, for example, bismuth and selenium compounds tethered in layered structures. These elements are expensive and have toxicity issues. To tackle these challenges, this study aims at constructing hybrid films of advanced thermoelectric performance by combining the increased electrical conductivity of zinc oxide and the thermal insulation of cellulose, i.e., the most abundant biopolymer. Layer alternation was achieved via consequent steps of spin coating nanocellulose and atomic layer deposition of zinc oxide. The alternating organic/inorganic layers were characterized by atomic force microscopy and x-ray reflectivity. Electric and thermal conductivity measurements were applied to assess the thermoelectric performance of the multilayer structures. Overall, a new route of fabricating thermoelectric films was revealed.
Authors : Ziyauddin Khan,* Ujwala Ail, Fatima Nadia Ajjan, Jaywant Phopase, Nara Kim, Olle Inganäs, Magnus Berggren, Xavier Crispin
Affiliations : Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-601 74 Norrköping, Sweden
Resume : In electrochemical energy storage devices, electrolyte solutions are essential. Alike electrodes, electrolytes also effect the performance such as specific energy, cyclic stability, longevity and self-discharge of device. Herein, we have synthesized a cost effective and environment friendly polyacrylic acid-based water in salt (WIS) electrolyte and used it to fabricate a device which include wood-based lignin with carbon as positive electrode and polyimide with carbon as negative electrode. The cost-effective biopolymers based pseudocapacitive device in WIS displayed a maximum of 16 Wh/kg specific energy, 6800 W/kg of power density, good cyclic stability (65% retention in specific capacity) up to 2500 cycles and remarkably slow self-discharge rate. The open circuit potential drops to 0.67 V from initial 1.7 V in 5 days. Our study can provide a facile pathway to assemble a cost-effective, environment friendly, stable and safe lignin based electrochemical energy storage device.
Authors : Xavier Aeby1, Alexandre Poulin1, Gilberto Siqueira1, Gustav Nyström1,2
Affiliations : 1 EMPA – Swiss Federal Laboratories for Material Science and Technology, Switzerland 2 ETH – Swiss Federal Institute of Technology, Switzerland
Resume : We report a fully printed (Direct-ink-Writing) nanocellulose-based supercapacitor with a specific capacitance of 5 F/g, a state-of-the-art performance for fully printed supercapacitors. With the exponentially growing number of sensors and connected-objects brought by the Internet-of-things era, the development of recyclable materials and sustainable manufacturing techniques is of crucial importance. The supercapacitor we present here is exclusively composed of biosourced materials and carbon. In particular, we use nanocellulose as a rheology modifier, structural material and binder in the development of several functional inks. The device is printed as two half-cells that are then folded together to form a 1 mm thick and 2.25 cm2 working device. Each half-cell is composed of four different layers: substrate, current collector, electrode and electrolyte. A substrate of plasticized cellulose is first printed, resulting in a low-surface roughness (2.5 μm RMS) and flexible substrate. A metal-free current-collector is printed on top of the substrate, exhibiting an electrical conductivity of 200 S/m and a surface resistance of 20 Ω/□. An hygroscopic cellulose-carbon electrode and a glycerol- NaCl electrolyte are subsequently printed on top of the current collectors. The materials and fabrication processes presented in this work advance the field of printed electronics and could be used for the fabrication of other passive and active components, from simple wiring to eco-friendly sensors.
Authors : Ujwala Ail*, Jaywant Phopase, Fatima Nadia Ajjan, Magnus Berggren, Olle Inganäs and Xavier Crispin
Affiliations : Laboratory of Organic Electronics, ITN, Linköpings Universitet, SE-60174 Norrköping, Sweden
Resume : The use of carbon-free renewable energy sources are needed to create a sustainable society. However, the two most popular sources of renewable energies; namely the solar and wind power are intermittent, they cannot match with the energy demand of human activity. Hence large-scale batteries are emerging as integral components of the energy solutions for the future to enable constant power delivery on the electrical grid. The current technologies for large scale electrical energy storage are based on the materials that have limited abundance or expensive to manufacture. In this regard, we report the development of a safe and sustainable bio-based battery components using materials that are abundant and recyclable. Lignin being one of the most abundant biopolymers, meets the requirement, as it has quinone-aromatic chemical groups that can be employed to store and deliver electrical charges by reversible Faradaic reactions. But lignin is also an electrical insulating material. To enable those Faradaic reactions, we composite lignin with a conducting polymer and obtain a nanocomposite that is conducting electricity and thus provide electrons and ions to lignin. More specifically, we report the preparation and optimization of the composite electrode containing lignosulfonate (LS) (lignin) and the conducting polymer (poly 3, 4-ethylenedioxythiophene; PEDOT) for energy storage application. Scaled-up synthesis route in aqueous media for low-cost environmentally friendly technology to make large volume batteries will be discussed. The results of the battery concept incorporating this lignin/PEDOT based-positrode) and a bio-based negatrode; PACA (poly(1-amino-5-chloroanthraquinone)/PEDOT in a water- based electrolyte along with cellulose based separator will be presented.
Authors : Sai Rashmi Manippady, and Manav Saxena
Affiliations : Centre for Nano and Material Sciences, Jain University, Bangalore, Karnataka-562112, India
Resume : The conversion of biomass into valuable carbon composites as an efficient non-precious energy storage electrode material has elicited extensive research interests. As synthesized partially graphitized iron oxide-carbon composite material (Fe3O4/Fe3C@C) shows an excellent property as an electrode material for supercapacitor. X-ray diffraction analysis, high resolution transmission electron microscopy, X-ray photo-electron spectroscopy and Brunauer-Emmett-Teller analysis is used to study the structural, compositional and surface areal properties. The electrode material shows a specific surface area of 827.4 m2/g. Due to the synergistic effect of graphitic layers with iron oxide/carbide, Fe3O4/Fe3C@C hybrid electrode materials display high-performance for supercapacitor with excellent capacity of 878 F/g at a current density of 5 A/g (3-electrode) and 211.6 F/g at a current density of 0.4 A/g (2-electrode) in 6M KOH electrolyte with good cyclic stability.
Authors : Martin Höglund* (1), Mats Johansson (1), Lars A. Berglund (1,2)
Affiliations : (1) KTH Royal Institute of Technology, Dept. of Fibre and Polymer Technology, SE-100 44 Stockholm, Sweden (2) Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
Resume : Transparent wood with high strength and low thermal conductance has shown potential as an energy-saving building material with high optical transmittance. However, the transmittance degrades with material thickness due to high haze, which mainly stem from scattering of light at interfaces between the wooden template and the polymer matrix. In this work, such scattering interfaces were limited by introducing a low polymerization shrinkage thiol-ene thermoset as a matrix into a modified lignin wood template. The transparent wood was found to have a significantly lower haze due to favorable interactions between the thermoset and the modified lignin template. Delignified wood templates, commonly used for transparent wood, were also tested and did not show a similar decrease in haze.
Authors : Sergii G. Nedilko
Affiliations : Taras Shevchenko National University of Kyiv, Kyiv Ukraine
Resume : There are many examples of development of devices, which use materials elaborated on the base of cellulose. Those are sensors, drives, flexible electronics components, etc. However, cellulose and derived materials are not often used or studied as optical systems or systems where optical phenomena can be inquired. The development of solar radiation dosimeters consisting of an organic dye and titanium oxide as a photocatalyst printed on the cellulose substrate is one of the examples. Cellulose fibers containing specific luminescent compounds as markers and simultaneously as effective modifiers for textile products, papers and plastic is other example. The aim of this work was to develop micro/nanostructured composites based on microcrystalline cellulose (MCC) as matrix and oxide compound as filler. The essential advantage of oxide fillers is their stability. In this work we described the procedure of synthesis, manufacturing, structural and optical (luminescent) characteristics of the MCC – oxide composites made by cold pressing method. Simple oxides (ZnO, ZrO2) as well as complex oxides (BiPO4:Eu; K2Eu(PO4)(MoO4)) were incorporated into MCC matrix. Some carbon species (CNT, graphen, expanded graphite) were added to the composites as modifiers. Characteristics of these composites were compared to characteristics of similar compositions prepared on the base of nanocellulose. The morphological, structural and optical, especially luminescence, characteristics were studied that confirmed the perspectives of practical application of the composites under study. The correlation between structural, morphological characteristics and physical properties of composites was found and discussed.
Authors : Céline Montanari* (1), Peter Olsén (1), Lars A. Berglund (1)
Affiliations : (1) Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, KTH Royal Institute of Technology, Teknikringen 56, 100 44 Stockholm, Sweden
Resume : Transparent wood (TW) is an attractive cellulosic-based composite for optically transparent and structural applications. TW is obtained from native wood veneer via a three-step procedure that includes the removal of the lignin, modification of the delignified wood template, and subsequent infiltration by a polymer matrix with matching refractive index. However, the chemicals used to remove the lignin (e.g. sodium chlorite), modify the template (e.g. pyridine, DMF) and the infiltrated polymer systems (e.g. polymethyl methacrylate, epoxy) are petroleum-based and environmentally hazardous. This study presents a sustainable TW alternative with comparable materials properties as previously reported for petroleum-based TW composites. The fully bio-based TW was prepared via an environmentally friendly delignification method followed by a green surface activation of the template. Subsequently, a novel bio-renewable acrylic monomer was synthesized and infiltrated in the wood template. The morphology of the materials, the physical, optical and thermo-mechanical properties of the bio-based TW were investigated.
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|08:45||PLENARY SESSION 2|
Authors : Francon H.*(1), Wang Z.(1), Marais A.(1), Mystek K.(1), Piper A.(1), Granberg H.(2), Malti A.(1), Gatenholm P.(3), Larsson P.A.(1) & Wagberg L.(1)
Affiliations : (1) KTH Royal Institute of Technology Dept. of Fibre and Polymer Technology, Sweden (2) RISE Innventia AB Papermaking and Packaging, Sweden (3) Chalmers University of Technology Dept. of Chemistry and Chemical Engineering, Sweden
Resume : In pursuance of the Paris Agreement’s climate goals, our societies must promptly transition towards renewable energies. Unlike their fossil counterparts, renewable energies inherently rely on intermittent sources (i.e. sunlight, wind and tidal power) and need to be stored to further meet the variations of the electric demand on the power grid. Consequently, there is a growing societal need for the production of low-cost and high-capacity energy storage materials, preferably from renewable resources. The forest, pulp and paper industries could play a key role in this transition, possessing infrastructures designed for large-scale preparation of renewable materials and aiming at new high-added value applications for their wood-based products. Among the different available wood derivatives, cellulose nanofibers (CNFs) have shown great promise in the design of durable, environmentally friendly and high-capacity energy storage materials. Owing to their high aspect ratios (diameter = 4 nm, length = 1–5 µm), CNFs have unique colloidal properties that enable the preparation of materials showing a wide array of structures such as films, foams, aerogels or nanocomposites. These materials are readily functionalized with electrically-active materials, making them suitable for energy storage applications. For that purpose, conjugated polymers such as polyethylenedioxythiophene (PEDOT) are of a great interest, showing a high electrical conductivity as well as a great chemical affinity towards CNFs. In this study, we present a novel, efficient and environmentally friendly method for preparing nanoporous materials – also referred to as aerogels – from CNF and alginate, a biopolymer extracted from brown algae. Based on successive freezing, thawing and ambient-drying steps, this simple method could meet the industrial requirements both in terms of production rate and energy consumption. The present findings indicate that these aerogels can be given virtually any shape (using 3D-printing) while also displaying tunable microstructures and mechanical properties (by controlling the ionic conditions during preparation). Using a scalable in-situ polymerization procedure, the aerogels can be functionalized with high loadings of PEDOT nanoparticles (as high as 1.7 g g-1), providing them with high electronic conductivity (146 S m-1) and specific capacitance (78 F g-1) and consequently enabling their use as energy storage materials.
Authors : M. Rothammer1, M.-C. Heep2, G. Zyla3, E. Gurevich3, G. von Freymann2,4 and C. Zollfrank1
Affiliations : 1Chair for Biogenic Polymers, Technical University of Munich, Germany 2 Physics Department and Research Center OPTIMAS, University of Kaiserslautern, Germany 3 Chair of Applied Laser Technologies, Ruhr-Universität Bochum, Germany 4 Fraunhofer Institute of Industrial Mathematics ITWM, Germany
Resume : The polysaccharide cellulose is next to chitin the most abundant biopolymer on earth and is considered an almost inexhaustible source of raw material for the increasing demand for environmentally friendly and biocompatible products. We recently synthesized a bio-based photoresist, where a photo-reactive cellulose-derivative is dissolved in an organic solvent together with a photoinitiator. This novel photoresist is curable by two-photon absorption at 780 nm in a direct laser writing (DLW) system (Nanoscribe Photonic Professional GT). With this setup, two-dimensional architectures with a linewidth of less than 250 nm and a minimum line distance of 500 nm are achieved. Our bio-based photoresist allows three-dimensional structuring of cellulose on the µm scale via DLW. Curing of our cellulose derivative is generally possible in liquid and solid state via two-photon absorption. In contrast to common photoresists, which are based on polymers sourced from mineral oil, our approach conserves resources through replacing those polymers by sustainable materials such as polysaccharides. The presented research includes the functionalization of cellulose to enable photo-crosslinking for generating biopolymer-based hierarchical architectures. This chemical modification is a prerequisite for the fabrication of two- and three-dimensional structures by DLW. Disorder on the nano-scale is created by the surface roughness of the DLW-fabricated structures and can be tuned via the concentration of the photoinitiator. Moreover, this polysaccharide-based photoresist enables manufacturing of biomimetic architectures, which consist entirely of a natural bulking material. Additionally, this cellulosic photoresist is curable via one-photon absorption with a UV-lamp (365 nm) in liquid as well as in dried state. Our resist opens up a new class of photo-curable polymers based on sustainable and renewable materials.  D. Klemm, et al. Angew. Chem. Int. Ed. 2005, 44, 3358.  M. Rothammer, et al., Cellulose 2018, 25, 6031.
Authors : Sai Rashmi Manippady, Manav Saxena
Affiliations : Centre for Nano and Material Sciences, Jain University, Bangalore, Karnataka-562112, India
Resume : Concerns about sustainability, environ benignity in material science to develop new electrode materials have attracted a great interest in renewable materials from nature as emerging solutions to a range of technological challenges. In particular, bio-derived materials are not only biocompatible and earth-abundant but also have nature-provided intrinsic structures for potentially transformative impact. Herein, we are presenting the room temperature synthesis of lignin/cellulose based electrode material for energy storage device (e.g. supercapacitor). The as synthesized material shows capacitance ~1005 F/g at discharge current density of 2 A/g in 6M KOH as calculated using GCD. Such lignin/cellulose material has potential applications in development of sustainable, eco-friendly electrode material for energy application and for academic and industrial applications.
Authors : Babak Ziaie
Affiliations : Purdue University
Resume : I this talk, I will discuss the use of direct laser writing on commercially available hydrophobic papers as a low cost and potentially scalable technique to rapidly prototype and manufacture a variety of microfluidic and transducing components and devices. Ubiquitous availability of cheap hydrophobic-layer-coated papers for culinary and food products combined with the bench-top lab-scale CO2 laser systems capable of selectively scanning and converting hydrophobic to hydrophilic regions allows for mask-less fabrication of disposable paper-based devices. After a brief description of the laser assisted fabrication technique, I will discuss several devices developed in my lab over the past few years including a variety of sensors targeted for interrogation of wound microenvironment. Next, I will describe a flexible smart wound dressing/patch capable of generation (via catalytic conversion of hydrogen peroxide delivered via a network of microfluidic channels) and sensing (via an integrated optical sensor) of oxygen fabricated using an integrated paper-PDMS platform. Finally, I will discuss challenges and opportunities in developing scalable manufacturing processes for successful commercialization of paper-based devices.
Wearables : Babak Ziaie
Authors : Sameer Sonkusale
Affiliations : Tufts University
Resume : This talk will explore the new realm of using threads as an ultimate platform for flexible and stretchable devices. Threads offer unique advantages of universal availability, low cost, material diversity and simple textile-based processing. In this talk, I will report reel-to-reel fabrication to make functional smart threads for variety of sensing and electronics application. For example I will report on nanomaterial-infused smart threads for strain and temperature sensing. Threads will be presented for sensing pH, glucose, and other chemical biomarkers. Interestingly, threads also provide an ideal platform for passive microfluidic sampling and delivery of analytes. I will show our recent work on using this toolkit of thread-based microfluidics, sensors and electronics for application as surgical sutures and flexible smart bandages for chronic wounds. Our recent work on using threads for closed loop spatiotemporal dosage controlled drug delivery will also be presented. I will conclude the talk by providing an outlook on future research directions in the field of textile-based flexible bioelectronics.
Authors : Nara Kim, Ziyauddin Khan, Fareed Ahmed, Samuel Lienemann, Klas Tybrandt*, Xavier Crispin*
Affiliations : Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden
Resume : With the rapid growth of wearable electronics and IoT, there is an increasing demand for compatible power sources such as wearable batteries. Organic biopolymer composites which combine electrical conductivity and redox activity have emerged as a promising class of electrode materials to realize cost-effective, eco-friendly and flexible batteries. However, the lack of stretchability and elasticity has limited their applications in wearable batteries that must function under dynamic and repetitive mechanical stresses. Here, we report a quaternary biocomposite that combines high electrical and ionic conductivity, originating from the conducting polymer and ionic liquid components, with the high energy storage capacity of nature-based quinones, and superior mechanical properties of a polyurethane elastomer matrix. The incorporation of multiple functionalities from different components was successfully achieved by the formation of favorable percolation networks and dynamic bonding between the components. Based on the strong adhesion of the polyurethane matrix, in combination with a polyether-polyurethane-ionic liquid electrolyte, we demonstrate all-organic solid-state stretchable batteries by laminating elastic electrodes and electrolyte produced from aqueous blends of composites.
Authors : Manuel Pietsch, Stefan Schlisske, Martin Held, Noah Strobel, Alexander Wieczorek, Gerardo Hernandez-Sosa
Affiliations : Light Technology Institute, Karlsruhe Institute of Technology, Engesserstrasse 13, 76131 Karlsruhe, Germany; InnovationLab, Speyerer Straße 4, 69115 Heidelberg, Germany
Resume : Biodegradable electronic devices gain a lot of interest in research in the past years, since the negative influence of e-waste on our world and our quality of life is dramatically increasing. Among electronic devices, wearables are a rapidly growing field in research combining conformable, stretchable and electronic properties. Possible applications are electronic skin, on-skin diagnostics or displays. The branch of wearable electronics will benefit from up-scalable, low-cost production methods like printing techniques. Wearables will be considered disposable due to short lifecycles and therefore massively contribute to the amount of e-waste. The use of biomaterials in electronic devices is one way to enhance sustainability. Electrochromic devices thereby provide opportunities for developing low-cost, biodegradable display applications. They´re advantages are low power consumption, low operating voltages and a simple device architecture. Here, we present on a biodegradable, wearable electrochromic display, which was fully produced by inkjet printing. Furthermore, its biodegradability was validated according to the international standard ISO 14855, demonstrating the successful use of biomaterials in electronic devices. The electrochromic devices were fabricated on a biodegradable cellulose di-acetate substrate. Gold electrodes and the electrochromic poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) layer were deposited via inkjet-printing. Finally, the devices were encapsulated by a gelatin-based electrolyte. The influence of different natural salts on the device performance was investigated. The finalized electrochromic displays change reversibly between a transparent and a deep blue state with high contrast. Its adhesive and conformable properties enable the use of the displays as wearables directly on skin. The fabricated devices exhibit a sufficient contrast, efficiency and lifetime to be used in disposable, biofriendly consumer and health care applications.
Authors : L. Manjakkal, A. Pullanchiyodan, R. Dahiya
Affiliations : Bendable Electronics & Sensing Technologies (BEST) Group, School of Engineering, University of Glasgow, G12 8QQ, UK
Resume : Electronic textiles (e-textiles) attracted huge attention as they enable advances in numerous applications ranging from health monitoring sensors, energy storage, energy generators to wireless systems. Considering the advances in energy autonomy for digital health and self-health management and monitoring, e-textiles have potential scope in energy storage applications for powering the sensors and electronics in wearable systems. In this work we fabricated a wearable supercapacitor (SC) on cellulose/polyester based cloth with PEDOT: PSS electrode as an electrode. Here the PEDOT: PSS coated cloth act as both current collector and active material of the SC. We observed that, the excellent wet absorption capacity of the cloth due to the polyester content in it (55% cellulose and 45% polyester) adsorb the PEDOT: PSS solution in the bulk of cloth material. The electrochemical properties of the SCs were investigated in three type of electrolytes such as H3PO4, sweat (artificial and human) and room temperature ionic liquid. Among this, SC in H3PO4 electrolytes shows excellent performance (the lowest value of equivalent series resistance (ESR) is 2.2 Ω). However considering the wearability, SC in sweat shows more suitability with electrolytes biocompatibility and easy to replenishing. The fabricated SC shows energy and power density of 1.36 Wh. kg-1 (1.63 µWh.cm-2) and 329.70 W.kg-1 (0.40 mWcm-2) respectively for 1.31 V (its specific capacitance 5.65 F.g-1) in an artificial sweat.
Authors : Ting Yang Nilsson(1)*, Xin Wang (2)
Affiliations : (1) Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-601 74, Norrköping, Sweden; (2) RISE Acreo, Box 787, SE-601 17, Norrköping, Sweden RISE * lead presenter
Resume : Electronic textiles are fabrics that have incorporated electronics for medicine, health monitoring and other functional purposes. Using wood cellulose in electronic textiles will enable comfortable, biocompatible and sustainable products. In this work, a new and efficient nonwoven technique solution blown was used to produce flexible conductive wood cellulose nonwovens. This technique introduces conductive carbon black (CB) nanoparticles in the cellulose solutions prior the fiber formation. The flexible and continuously regenerated cellulose/CB fiber filaments were formed by extruding the solution through multiple micro-nozzles and drawn by high velocity air to form fiber networks. The process allows versatile tailoring of functionalities of the cellulose and varying of the microstructures and the porosity of the nonwoven. The relationships between the material properties and process parameters have been explored. The scanning electron microscopy study showed that the CB and cellulose were combined homogenously; the fiber diameters were varied from 1-100 µm for different processes. For the nonwovens with the same CB/cellulose ratio, the 4-point probe measurements showed that the area resistance was decreased from ca. 5000 Ω/□ to 700 Ω/□ with decreased porosity. The moisture content also showed effect on the area resistance. The nonwoven has charge storage capability. Promising applications include, e.g., energy storage, moisture sensors and near body heater.
Authors : Do Van Lam, Sejeong Won, Hak Joo Lee, Hyung Cheoul Shim, Jae-Hyun Kim, Seung-Mo Lee
Affiliations : Do Van Lam; Hyung Cheoul Shim; Jae-Hyun Kim; Seung-Mo Lee Department of Nanomechanics, Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon 34103, Korea Sejeong Won; Hak Joo Lee Center for Advanced Meta-Materials (CAMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon 34103, Korea
Resume : Cotton is established as an innovative foundation for smart wearable energy storage devices with appealing properties. The challenge is that the current approaches using either additional coating or direct carbonization mostly lead to mechanically fragile or electrochemically poor textile. We demonstrate that the coating of metal oxide on the cotton and subsequent pyrolysis readily turn cotton into the conductive textile with high porosity and excellent toughness. The resulting textile has an energy density of 2.24 mWh/cm3 (nearly 3 times higher than other commercial supercapacitors) and a power density of 585 mW/cm3 (over 2-orders-of-magnitude higher than that of the lithium battery). We show that the metal oxide assisted carbonization allows metal atoms to migrate into the graphite-like layers of the carbonized cotton. It appears that the migrated metal atoms and the phase transformation of the coated metal oxides play a critical role in considerable changes in the microstructure and porosity of the carbonized cotton.
Authors : Shivam Gupta*, Nyan-Hwa Tai
Affiliations : Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Sec. 2, Guang-Fu Road, Hsinchu, Taiwan 300, ROC.
Resume : Due to the intensive growth of electronics and telecommunications, electromagnetic (EM) pollution has become a serious concern of the modern world. Apart from the public health impact of EM pollution, such as brain tumor and leukemia, it also causes interference to the working of many nearby devices. In this regard, wearable electromagnetic interference (EMI) shielding materials such as conducting textiles have emerged to protect human as well as sensitive electronics from EM pollution. In this work, zinc oxide (ZnO) and reduced graphene oxide (rGO) coated wearable cellulose-based textile are prepared for the application of EMI shielding in X-band (8.2-12.4 GHz). The uniform coating of ZnO nanoparticles is achieved by the in-situ sol-gel method, whereas the uniform coating of rGO is achieved by simple spraying of graphene oxide solution followed by thermal reduction. The total EMI shielding effectiveness increases with the rGO loading, however, the return loss decreases owing to improved conductivity of the fabric. The as-prepared rGO/ZnO coated cotton achieves high total EMI shielding effectiveness of ~99.999% (54.7 dB), which is shared by ~17.783% of reflection and ~82.216% of absorption. Such high absorption dominant EMI shielding is attributed to highly conductive rGO sheets, highly dielectric ZnO nanoparticles and the core-shell structure of the coated cotton fabric. Keywords: Cellulose-based composites, Wearable electro-conductive textile, EMI shielding
|18:30||AWARD CEREMONY followed by SOCIAL EVENT|
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|08:45||PLENARY SESSION 3|
No abstract for this day
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