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BIOMATERIALS

J

Electronic textiles

With their numerous technological applications, fiber based structures, like those found on clothes and furniture, are steadily making their way into high technological areas like the car industry, and medical and healthcare sectors. Advances in material science and nanotechnology have made it now feasible to build electronic devices directly on the surface or inside single fibers, thereby providing a unique opportunity to create smart and functional electronic textiles. At present, electronic textiles are becoming a very hot topic attracting a great interest of academic and industrial researchers. European research groups have produced a growing amount of publications combining electronics devices and materials with textiles. We consider that the MRS conference is highly positioned to disseminate such results.

Scope:

This symposium will represent a unique opportunity to gather together experts from different research and industrial field working on electronic textiles. This research field has a strongly multidisciplinary character as it requires an extremely wide range of expertise and skills, spanning from materials, physics, chemistry, engineering, medicine and social issues. The focus is on fiber–based structures with novel smart functionalities that allow to envisage innovative and breakthrough applications in wearable and textile related technologies. The attention is not limited to the characterization, design, and development of novel materials, smart textiles and sensing devices, but it also targets technologies related to the interconnection of textile electronics functionalities leading to smart networks and to the development of hybrid approaches integrating flexible devices with traditional solid state electronics.

Technology transfer issues are particularly relevant for new classes of high-tech materials and products and this symposium is very keen on devoting a special session on this topic, addressing the challenges and the opportunities faced by start-ups and small high tech companies interested in investing in this exciting and fast growing research field.

Hot topics to be covered by the symposium:

  • Materials for functional fibers
  • Smart Fabrics and Interactive Textiles
  • Hybrid structures inspired form organic and solid state electronics
  • Flexible embedded systems in wearable technologies
  • Innovative interconnect technologies for textiles
  • Textile sensors, systems, circuits
  • Wearable computing and communication systems
  • Textile energy harvesting and storage
  • Technology transfer: From the fiber to the garment to the market

List of confirmed invited speakers:

  • Annalisa Bonfiglio (University of Cagliari, Italy)
  • Genevieve Dion (Drexel University, USA)
  • Thierry Djenizian (EMSE, France)
  • Yury Gogotsi (Drexel Nanomaterials Group, USA)
  • Mahiar Hamedi (Harvard University, USA)
  • Toshihiro Itoh (University of Tokyo, Japan)
  • Christine Kallmayer (Fraunhofer IZM, Germany)
  • Vladan Koncar (ENSAIT, GEMTEX laboratory, France)
  • Luigi Occhipinti (University of Cambridge, England)
  • Rebeccah Pailes-Friedman (Interwoven design group, USA)
  • Nils-Krister Persson (University of Boras, Sweden)
  • John A. Rogers (University of Illinois, USA )
  • Janos Vörös (ETH Zürich, Switzerland)

Publication:

Together with E-MRS and Wiley, Symposium J has organized an opportunity for publishing our findings in a Special Issue (focus: Electronic Textiles) of Advanced Materials Technologies. AMT is new to the Advanced Materials series, and focuses specifically on "advanced device design, fabrication and integration, as well as new technologies based on novel materials. It bridges the gap between fundamental laboratory research and industry.” This opportunity for publishing in Advanced Materials Technologies is automatically open to all invited speakers, with all contributors welcome to submit a manuscript.

Awards:

One Best Student Oral or Poster Presentation Award will be provided by the symposium J and its sponsors Heraeus and E-MRS. The winner will be nominated on the last day of the Symposium J.

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Smart Fabrics and Interactive Textiles - Welcome by Symposium J organizers : Esma Ismailova, Tobias Cramer, Daniel Simon
14:00
Authors : Xuyuan TAO 1, Vladan KONCAR 1, Tzu-Hao HUANG 2, Chien-Lung SHEN 2,3, Ya-Chi KO 2, Gwo-Tsuen JOU 3
Affiliations : 1 Ecole Nationale Supérieure des Arts et Industries Textiles, 2 allée Louise et Victor Champier, 59056 Roubaix Cedex 1, France 2 Department of Products, Taiwan Textile Research Institute, No.6, Chengtian Rd., Tucheng Dist. New Taipei City, 23674, Taiwan (R. O.C.) 3 Department of Bissness and Planning, Taiwan Textile Research Institute, No.6, Chengtian Rd., Tucheng Dist. New Taipei City, 23674, Taiwan (R. O.C.) 4 Department of Biomedical Engineering, National Yang-Ming University, No.155, Sec.2, Linong Street, Taipei,112 Taiwan (R.O.C.)

Resume : In this study, the washability of smart textile devices has been studied. Two different approaches aiming at designing, producing and testing robust washable and reliable smart textile systems are presented. The common point of two approaches is the use of flexible conductive PCB in order to interface the miniaturized rigid (traditional) electronic devices to conductive threads and tracks within the textile flexible fabric and to connect them to antenna, textile electrodes, sensors etc. The first approach is focused on the protection of the whole system composed of rigid electronic device, flexible PCB and textile substrate by the barrier made of latex. The second approach consists in the use of TPU films (thermoplastic polyurethane) that is deposited by the press under controlled temperature and pressure parameters in order to protect the electrical contacts. Several prototypes were realized and washed. Their reliabilities are studied. The “Wearable Technology industry” as an important sector of overall “Smart Textile industry” may be perceived as a newly defined industrial segment derived from the convergence of many incumbent sectors such as flexible and miniaturized electronics, technical textiles, membranes and barrier insulation etc. This new industrial sector has numerous fields of applications capturing and emphasizing several key trends such as sports and leisure, healthcare, military, and security apparel, fashion consumer electronics. According to the 2016 IDTech Exhibition Report, the Compound Annual Growth Rate (CAGR) will be 37% for smart watches, 34% for medical devices, 146% for smart sports apparel and 585% for AR&VR (Augmented and Virtual Reality) eyewear devices from 2015 to 2018. In most wearable technology industries, textiles play an important role as substrate for sensors and actuators, user-end devices and communication platforms. With the development of material science and electronic engineering, the wearable textile devices are tremendously miniaturized and their form moves from bulky and rigid to thin and flexible. More and more devices become invisible and ubiquitous for end-users. The user-machine interfaces become more friendly and the wireless systems are extensively involved in the transmission of vital signs monitoring, motion, etc. However, the washability issue is always an obstacle in terms of application reducing the reliability of smart textile devices and making them not robust enough and therefore not ready for the market. Many of experimental wearable textile devices cannot be used in the real life because of the washability problem. Due to the capillary effect, even the hydrophobic textile substrate can still absorb the water in the textile bulk and make electronic devices fail. Besides, the mechanical stresses provoked by the washing process may destroy the electrical contacts between the conductive thread and the electronic wearable device. As a result, the electric impedance becomes uncontrollable after several cycles of washing process and the wearable device becomes unstable and in some cases stops to function.

J.1.1
14:30
Authors : Jiuk Jang, Byung Gwan Hyun, Sangyoon Ji, Eunjin cho, Jang-Ung Park
Affiliations : School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Republic of Korea

Resume : Recently, transparent heaters require flexibility and stretchability as the parts of future electronics. The stretchable and transparent heaters have been applied to various applications such as defogging a window and thermal therapy for medical treatment. Although indium tin oxide (ITO) has been used as the resistive heater, it has mechanical limitations due to its intrinsic fragility. Meanwhile, the wireless communication becomes essential for the convenience of users in wearable electronics. Here, we demonstrate a stretchable, transparent and large-area resistive heater on various substrates using the random network of the ultra-long Ag nanofibers (AgNFs). Optical transmittance and the sheet resistance of electrode can be controlled by adjusting area fraction of AgNF random networks; therefore, various temperature range and power consumption can be achieved depending on the purpose. The heater presents high temperature (250 ºC) at a low operating voltage and excellent temperature reliability under large strain (40%). In addition, we integrated the heater with wireless operation system by connecting Bluetooth module so that the temperature is controlled directly using smart devices. According to the target purpose, temperature also can be automatically controlled by applying logic circuit on the micro-controller unit. We believe these stretchable and transparent large-area heaters with the wireless operation systems can be a solution for future wearable electronic devices.

J.1.2
14:45
Authors : Doga Doganay, Sahin Coskun, Sevim Polat, Husnu Emrah Unalan
Affiliations : Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara 06800, Turkey

Resume : Modification of insulating fabrics with electrically conductive nanomaterials opened up a novel application field. With the help of Joule heating mechanism, conductive fabrics can be used as mobile heaters. In this work silver nanowires (Ag NWs) were used for the fabrication of heatable textiles. Cotton fabrics were simply decorated with Ag NWs via dip and dry method. Time dependent thermal response of the fabrics under different biases was investigated. It was found that the fabrics can be heated to 50 °C under an applied power density of 0.05 W/cm2. Uniform deposition of Ag NWs resulted in the homogeneous generation of heat. In addition, we have examined the stabilities of the fabrics with time and under different bending and washing conditions. The heating performance of the fabrics remained unchanged after 5000 bending cycles. Moreover, a simple thermostat circuit was fabricated and integrated in order to demonstrate the high potential of the fabrics for mobile applications.

J.1.3
15:00
Authors : Jason D. Ryan, Desalegn A. Mengistie, Anja Lund, Roger Gabrielsson, Christian Müller
Affiliations : Jason D. Ryan, Desalegn A. Mengistie, Anja Lund, Christian Müller Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden Roger Gabrielsson IFM, Linköping University, 58183 Linköping, Sweden

Resume : Durable, electrically conducting yarns are a critical component of electronic textiles (e-textiles). Here, such yarns with exceptional wear and wash resistance are realized through dyeing silk from the silkworm Bombyx mori with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. A high Young's modulus of about 2 GPa combined with a robust and scalable dyeing process results in up to 40 m long yarns that maintain their bulk electrical conductivity of about 14 S/cm when experiencing repeated bending stress as well as mechanical wear during sewing. Moreover, a high degree of ambient stability is paired with the ability to withstand both machine washing and dry cleaning. To illustrate the potential use for e-textile applications, an in-plane thermoelectric module that comprises 26 p-type legs is demonstrated by embroidery of dyed silk yarns onto a piece of felted wool fabric.

J.1.4
15:15
Authors : Luciano F. Boesel
Affiliations : Empa Swiss Federal Laboratories for Materials Science and Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland

Resume : “Smart textiles” encompasses a range of textile materials that react or adapt to physical stimuli (e.g., thermal, electrical, etc.), and combine both specialty materials and integrated computing power. They have found a stable place in the field of continuous monitoring of the human health, with numerous projects worldwide being pursued towards the monitoring of heart rate, temperature, movement and respiration, and muscle activity, among others. The specialty materials include optical fibers, conductive polymers, metals, or nanoparticle coatings. Here, I will describe the projects being carried out at Empa in the field of "smart textiles". This includes: a) a textile electrocardiogram (ECG) sensor, able to measure the ECG over long time periods and even on dry skin: this sensor works also for dry skin; b) a photoplestimograph (PPG), based on photonic textiles (textiles incorporating polymer optical fibers) to be used for the prevention of decubitus ulcers; this sensor may be used in reflexion to measure blood flow in any position of the body; c) a respiratory rate sensor based on pressure-sensitive optical fibers; and d) a biosensor for wound healing monitoring based on fluorescent textiles. Special emphasis will be put on sensors using affordable materials.

J.1.5
15:30
Authors : Ariana S. Levitt A, Chelsea Knittel A, Daniel Christie B, Dani Liub B, Yuqiao Liu C, Kapil Dandekar C, Caroline Schauer A, Antonios Kontsos B and Genevieve Dion D,*
Affiliations : A Department of Materials Science and Engineering, Drexel University, Philadelphia, United States B Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, United States C Department of Electrical and Computer Engineering, Drexel University, Philadelphia, United States D Department of Design, Drexel University, Philadelphia, United States

Resume : Metatextiles are fabrics that exhibit properties not usually found in conventional textiles. Conductive yarns and threads, including silver-coated nylon yarns and melt-spun carbon black blends, are widely used in metatextiles to provide flexible pathways for conducting electrical current. Several researchers have produced wearable sensors for health monitoring applications and shown promising results for short-term use however, few have studied the long-term performance of these devices. Like all garments, wearable sensors are susceptible to environmental factors such as humidity and precipitation, and are exposed to sweat and moisture during use. These factors may lead to dielectric coupling and corrosion of conductive yarns, which may significantly degrade the performance of the device. In a variety of fields, pre-production visualization and analysis tools have become ubiquitous, thereby transforming design and manufacturing processes and improving efficiency in manufacturing while reducing material waste and time to market. The design, fabrication and production of metatextiles could greatly benefit from the use of these tools but surprisingly there are very few on the market today. For example, knitted wearable antennas/sensors are often fabricated with silver-coated nylon yarns, yet limited modeling tools exist to evaluate the performance of knitted conductive yarns during production or use as a metatextile. Given the market pull for wearable electronics, the lack of validated design and predictive modeling methods has become a critical barrier to innovation. Through traditional methods, sliver coated nylon yarns were evaluated in terms of their reflection coefficient and radiation efficiency before and after mechanical stretching and exposure to sweat and moisture. Scanning Electron Microscopy (SEM) equipped with an energy-dispersive spectroscope was used to analyze the uniformity of the conductive coating. The results indicate that friction and abrasion during knit fabrication and exposure to sweat during use leads to degradation of the silver coating and decreased. The result of these findings were used to help inform our modeling tools, including finite element simulations that are used to compute resistivity and conductivity as a function of applied strain and knitted substrate material architecture.

J.1.6
16:00 Coffee break    
 
Poster Session : Annalisa Bonfiglio
16:30
Authors : Usein ISMAILOV, Esma ISMAILOVA
Affiliations : Department of Bioelectronics, Ecole Nationale Supérieure des Mines de Saint Etienne.

Resume : Textile-based large area humidity sensors are prepared using direct patterning of PEDOT:PSS conducting polymer ink. The sensing characteristics and the working mechanism are investigated by measuring the impedance spectra of the sensor at different humidity levels. The relation between the sensors geometry and its response are investigated in correlation with the sensory threshold. The textile sensors exhibit a quick response time and resistance to the humid environment. Large-scale devices can be fabricated using a roll-to-roll low cost patterning process. Such sensors can find their application in wearable electronics and instrumented textiles in medicine.

J.2.1
16:30
Authors : Tung Nguyen-Dang, Alexis Page, Yunpeng Qu, Wei Yan, Marco Volpi, Nadege Guedon, Prof. Fabien Sorin
Affiliations : Laboratoire des Fibres et Materiaux Photoniques - Institut des Materiaux - Ecole Polytechnique Federale de Lausanne - Lausanne - Switzerland.

Resume : Touch and pressure sensing systems that can cover large areas or even curved surfaces are becoming increasingly important in a variety of applications, ranging from healthcare monitoring to robotics and prosthetics. The functionalization of such systems is however usually achieved at the expense of spatial resolution, or at the cost of complicated fabrication schemes. Here, we present a simple and scalable method to fabricate hundreds-of-meters long touch-sensing electronic fibers with sub-millimeter spatial resolution along their entire length. We used the thermal drawing technique, the same technique used to make optical fibers, that enables to draw extended length of microstructured fibers with complex multi-material architectures. Two types of fibers will be discussed. A first one uses an electromechanical actuation to detect touch by bringing into contact two electrically conducting nanocomposite domains. This cantilever-like architecture embedded along the fiber length constitutes a novel and unique fiber structure with bendable electrically conducting parts (J. of Phys. D, accepted). A second type of fiber relies on a capacitive effect to sense light touch accurately. Finally, we will discuss the integration of such functional fibers into grids either by traditional weaving or by a novel imprinting process to create flexible functional surfaces. These highly flexible and sensitive fibers represent significant opportunities for smart textiles and wearable electronics.

J.2.2
16:30
Authors : Mingyuan Pei, Joong Se Ko, and Hoichang Yang
Affiliations : Department of Applied Organic Materials Engineering, Inha University, Incheon 22212, Korea

Resume : E-skin or E-texitile based on stretchable components (conductor, semiconductor, and insulator) have attracted tremendous attention, because they can well adhere to the human skin tissue to monitor the bio-signals without any interruption by dynamic motion artifact. Here, we investigate stretchable polymer-based organic field-effect transistors (OFETs) including conducting, semiconducting, and insulating polymers, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonates (PEDOT:PSSs), donor (D)-acceptor (A) copolymers, and thermoplastic elastomers (TPEs). First, to achieve highly stretchable semiconducting polymer layers, conjugated domains of several semiconducting polymers are dispersed in dilute solutions ultrasound-treated, and subsequently solution-blended with TPEs. Then, the semiconducting/TPE blended solutions are solution-cast onto solution-printed dielectric/gate electrode layers on a polymer supporting film. Electrical properties of the all polymer-based OFETs, which contain a bottom gate with top drain and source electrodes, are characterized under an applied strain, and they are correlated with the strain-dependent structural changes of each component in the corresponding OFET, as determined by morphologic and X-ray analyses.

J.2.3
16:30
Authors : Amine HAJ TAIEB; Slah MSAHLI
Affiliations : Institut Supérieur des Arts et Métiers de Sfax, Laboratoire Génie Textile, Institut Supérieur des Etudes Technologiques de Ksar Hellal

Resume : Innovations in textile products need to be in harmony with consumer’s needs (functionality, choice of colors, clothing line,...). In this paper integrating color in smart optical textile will be discussed. These products are the result of technological research in diverse fields A design concept for smart optical textiles is presented. The design describes utilization of fashionable technology for building those textile products. We describe the technical development of the concept of smart optical textile, and briefly discuss two challenges: materials and fabrication, and wear

J.2.4
16:30
Authors : Keana De Guzman, Aoife Morrin
Affiliations : Keana De Guzman, School of Chemical Sciences, Dublin City University, Ireland; Aoife Morrin,School of Chemical Sciences, Dublin City University Ireland, INSIGHT Centre for Data Analytics, National Centre for Sensor Research,

Resume : The human skin is the largest organ of the human body and is a subject of significant research interest since it can provide valuable insight into the health status of an individual. The stratum corneum (SC) is a layer of great interest from a dermatological point of view since it plays a critical role in the barrier function of the skin by protecting the underlying layer from infection, dehydration, and irritants. Epidermal sensors such as tattoo-based platforms have been recently used as they are simple to fabricate and have the potential for more intimate contact to the body compared to their textile-based counter parts.(1) A screen-printed tattoo sensor has been developed by ourselves as a step towards a simple, low cost, non-invasive wearable capable of measuring the impedance of skin and changes related to skin barrier function. The tattoo sensor was shown to impedimetrically track changes in hydration state (2) which were validated by tissue dielectric constant measurements taken with a commercial dermal probe.(3) The next step to improve the user benefit of this wearable device is to enhance its flexibility and conformability. To achieve this, the choice of materials and processing method is critical and one strategy in stretchable epidermal electronics is to combine a high loading of a hard component that is conducting with the overall mechanics that is dominated by a soft material for flexibility.(4) The use of conductive elastomeric composites will further improve the tattoo sensor platform in order to endure mechanical stress and mimic the behaviour of the epidermis. Here, we will present research on our screen-printed tattoo sensor used for skin barrier function tracking, and our latest developments around addressing its flexible and conformable needs. Reference (1) Bandodkar, A. J.; Jia, W.; Wang, J. Electroanalysis 2015, 562–572. (2) De Guzman, K.; Morrin, A. Electroanalysis 2016, 188–196. (3) Mayrovitz, H. N.; Grammenos, A.; Corbitt, K.; Bartos, S. Ski. Res. Technol. 2015 (4) Fan, J. A; Yeo, W.-H.; Su, Y.; Hattori, Y.; Lee, W.; Jung, S.-Y.; Zhang, Y.; Liu, Z.; Cheng, H.; Falgout, L.; Bajema, M.; Coleman, T.; Gregoire, D.; Larsen, R. J.; Huang, Y.; Rogers, J. A. Nat. Commun. 2014, 5, 3266.

J.2.5
16:30
Authors : Francesco Calavalle, Marco Zaccaria, Oliviero Bocchi, Tobias Cramer, Davide Fabiani, Beatrice Fraboni
Affiliations : Department of Physics and Astronomy, University of Bologna, Italy; Department of Electrical, Electronic and Information Engineering, University of Bologna, Italy; Centre for Advanced Applications in Mechanical Engineering and Materials Technology, University of Bologna, Italy;

Resume : Ferroelectric polymer fibres have promising properties for nanoscale electromechanical transducers with relevance for strain and pressure sensing or energy harvesting in textile electronics. Nanoscale fibres of the ferroelectric polymer PVDF-TRFE are accessible by electrospinning and have been successfully employed in wearable strain sensors. However, it is still unclear how the nano-confinement and high electric fields during electrospinning impact on ferro- and piezoelectric material properties. Here we present our investigations of single electrospun PVDF-TRFE fibres by Atomic Force Microscopy techniques. By observing the piezoelectric response as a function of the applied DC-field we demonstrate that polarization switching can be obtained in single fibres. Although the fibres experience a high electric field during the spinning process they remain in an unpolarised state. Instead an accumulation of negative space charge is observed that could explain the performance of unpolarised electrospun fibers in devices reported so far.

J.2.6
16:30
Authors : Alexander Goikhman
Affiliations : Research and Educational Centre “Functional Nanomaterials”, Immanuel Kant Baltic Federal University, Kaliningrad, Russia

Resume : The dressing materials are known as a first evidence of wound care and medicine origin in general since the prehistoric period. Until nowadays traditional gauze dressings, constructed from an open-weave fabric, usually cotton, function as an absorbent, are widely used. The usage of colloidal silver particles as disinfection substance was also known from Hippocrate writings [1], but at first time it was applied in the dressing materials in at the begging of XX century [2]. Since that time, the most of commercially available dressings with silver particles (like Silvercel by Johnson & Johnson, Atrauman Ag by Hartman etc.) are using that kind of silver (i.e. methods of wet chemistry). In this work, we report on the results of silver thin film nano-layers coating of gauze dressings by ion-plasma and magnetron deposition. The advantages of vacuum coating technology is discussed: significant decreasing of silver consumption, possibility to control hydrophobicity of dressing product by choosing the deposition particles energy etc. The treatment of infected wounds by thin film coated silver bandages also has been investigated. The possibility to apply an approach of smart textile to such type of innovative dressing materials is discussed. 1. Dai T et al., Recent Pat Antiinfect Drug Discov. 5 (2), 124–151 (2010) 2. Alexander JW, Surg Infect (Larchmt). 10, 289–92 (2009)

J.2.7
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Technology Transfer : Christine Kallmayer
09:00
Authors : Rebeccah Pailes-Friedman
Affiliations : IDSA

Resume : As the lines between computing and textiles blur, so do the lines between computing and our bodies. Wearable technology is evolving to a point where it pervades many aspects of our lives, and we have become accustomed to being surrounded with technological conveniences. Soon, our garments will become mobile devices that will seamlessly connect us to our networks, give and receive vital information through interfaces that become so integrated into our actions and activities that they become less invasive but more pervasive. Here we look at the application of electronic circuits and sensors onto textile in the creation of garment based wearables. These products have been engineered to feel and perform like a regular textile: they have drape, flexibility, are comfortable and durable. Once woven, sewn or printed into a garment or accessory, the general consumer can respond with much greater ease than with a traditional electronic device. Case studies will demonstrate the discovery and application of various methods of embedding circuits to textiles for wearable technology projects. The benefits of bringing technology ?out of the box? will revolutionize how we approach many aspects of our current lives.

J.3.1
09:30
Authors : Luigi G. Occhipinti, and Jong Min Kim
Affiliations : University of Cambridge, Department of Engineering Electrical Engineering Division, 9 JJ Thomson Avenue, Cambridge CB3 0FA United Kingdom

Resume : The vision of 1D-NEON is to develop fibre-based smart materials and integrated technology platforms for the manufacturing in Europe of high value-added smart textiles, with applications in Large-Area electronics, Energy, Sensing and Soft robotics. 1D-NEON builds on a modular platform where nanomaterials are assembled into five basic fibre components along with textile-based manufacturing processes for integration of e-fibre components into smart products. The project brings together 14 partners from 7 European countries active in advanced materials, design platforms, textiles, electronics and photonic sectors. The talk will review the main challenges of currently available state-of-the art technologies and discuss opportunities to bring innovation into key market sectors of e-textiles, with the help of selected new product examples and lessons learned, both from the 1D-NEON partners and others.

J.3.2
10:00 Coffee break    
 
Textile Energy Harvesting and Storage : Janos Vörös
10:30
Authors : Thierry Djenizian
Affiliations : Flexible Electronics Department, Ecole Nationale Supérieure des Mines de Saint-Etienne

Resume : Stretchable energy storage microsystems composed of thin-film supercapacitors and Li-ion microbatteries (µLIBs) have attracted attention to meet the requirements of autonomous wearable technologies such as shape-conformable portable wireless gadgets or smart textiles. With many advantages such as high surface area and improved charge transport, self-supported 3-D nanostructured metal oxides such as titania nanotubes (TiO2nts) are promising electrode materials for µLIBs [1-3]. This talk will review the concept and fabrication of all-solid-state µLIBs using TiO2nts as negative electrode. Fundamentals such as electrode reactions, lithium ion diffusion and the conformal electrodeposition mechanism of polymer electrolytes into nanostructured electrodes will be presented. The fabrication of a full 3D microcell showing high electrochemical performance will be shown and the development of the next generation of flexible and stretchable 3D microbatteries for electronic textiles will be discussed. References [1] B.L. Ellis, P. Knauth, T. Djenizian, Adv. Mater., 26 (2014) 3368. [2] N. Plylahan, M. Letiche, M. Barr, B. Ellis, S. Maria, T. N. T. Phan, E. Bloch, P. Knauth, and T. Djenizian, J. Power Sources, 273, 1182 (2015). [3] G. Salian, C. Lebouin, A. Demoulin, P. Knauth, M. Lepikhin, A. Galeyeva, A. Kurbatov, and T. Djenizian, J. Power Sources, 340, 242 (2017).

J.4.1
11:00
Authors : B. Friedel1, R. Schennach2
Affiliations : 1 Energy Research Center, Vorarlberg University of Applied Sciences, Dornbirn, Austria; 2 Institute of Solid State Physics, Graz University of Technology, Austria

Resume : Wearable electronics is a growing field of research and a quite large number of devices that are suitable for and would benefit from a direct integration in/onto clothing have been introduced. However, all of these devices need some form of electrical power. Due to weight increasing with capacity, batteries are not a good solution for wearable electronics. Therefore, different methods of energy harvesting have been proposed. Here mainly the wearer is targeted as a source of energy (e.g. kinetic energy from movement and thermal energy from body heat). However, most of these sources bring only very limited amounts of available charge. When a textile could be based on a photovoltaic fabric, enough energy for most electronic gadgets could be generated. In this paper we show a proof of principle device of an organic solar cell built on a single viscose fiber. The concept and the preparation of the device will be shown. All components of the presented photovoltaic device were applied using methods suitable for up-scaling to a roll-to-roll process. Finally, the electrical characteristics of such a device will be shown and discussed with respect to other organic photovoltaic devices.

J.4.2
11:15
Authors : Karin Rundqvist (1), Erik Nilsson (2), Christian Müller (3), Anja Lund (1,3)
Affiliations : (1) The Swedish School of Textiles, University of Borås, Borås, Sweden; (2) Textiles and plastics, Swerea IVF, Mölndal, Sweden; (3) Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden;

Resume : Wearable power supplies are a critical component in any wearable electronic system. Here we present a textile that generates electrical power from a ubiquitous source of “waste” energy; our body movements. We demonstrate how piezoelectric yarns can be fabricated through melt-spinning of PVDF into fibres with a core/sheath configuration. The core is a composite of 10% carbon black in polyethylene, and serves as the inner electrode. Electrically conducting yarns were used as the outer electrode, as this is the most suitable for practical applications. Melt spinning was carried out in a pilot scale spinning line at 800 m/min. We have fabricated woven straps where the piezoelectric yarn is combined with a variety of electrically conducting yarns. During cyclic stretching in a tensile tester, the straps repeatedly generate an output of several volts at a strain of 0.25%. The measured electronic output, which depends on the weave pattern and the properties of the conducting yarn, can be relevantly described with an LTspice-model. Its functionality is demonstrated by using our textile as the shoulder strap attached to a laptop case, which permits to scavenge energy during walking using a standard energy harvesting circuit.

J.4.3
11:30
Authors : Anaëlle TALBOURDET, François RAULT, Cédric COCHRANE, Aurélie CAYLA, Guillaume LEMORT, Eric DEVAUX, Anne GONTHIER, Christine CAMPAGNE
Affiliations : A Talbourdet(1,2); F Rault(1,2); A Cayla(1,2); C Cochrane(1,2); E Devaux(1,2); A. Gonthier(3); G Lemort(1); C Campagne(1,2) (1)ENSAIT, GEMTEX, 2 Allée Louise et Victor Champier 59100 Roubaix, France (2)Université Lille Nord de France, Cité Scientifique 59655 Villeneuve-d’Ascq, France anaelle.talbourdet@ensait.fr (3)CETI, 41 rue des métissages 59200 Tourcoing, France

Resume : Generating and harvesting energy offer new possibilities to smart materials such as textiles. The alliance of textile and electric technologies is necessary to develop piezoelectric fabrics: Indeed flexibility and energy creation are required for such components. To achieve the desired characteristics, PVDF piezoelectric fibres can be produced by melt spinning, because this polymer is able to have piezoelectric properties when crystallizing under a β-phase. Optimizing the content of β-phase is then a key challenge to developing such fibres. The transformation of non-polar α-phase to polar β-phase can be controlled by adjusting drawing ratio and processing temperatures. Firstly, the β phase content is optimized in PVDF, then the material is poling by contact to accentuate piezoelectric character by reorienting the macroscopic dipoles. Dynamic Mechanical Analysis (DMA) tests coupled to a Keithley voltmeter allow the solicitation of PVDF woven samples. A variation of voltage is obtained in compression. The second part involves the development of a tricomponent fibre. Two layers of conductive polymers acting as external/internal electrodes are placed on either side of the PVDF layer. Obtaining excellent interfacial adhesion between each layer is crucial for increasing the sensitivity of the electrodes. A new conductive property has been added to the piezoelectricity of the fibre in order to create a textile that can be used as a mechanical sensor and energy harvesting application.

J.4.4
11:45
Authors : Antti J. Karttunen, Liisa Sarnes, Riikka Townsend, Jussi Mikkonen, Maarit Karppinen
Affiliations : Department of Chemistry and Materials Science, Aalto University, FI-00076 Aalto, Finland; Department of Design, Aalto University, FI-00076 Aalto, Finland

Resume : Thermoelectric (TE) materials can be used to convert heat to electric energy and there is a significant interest in producing flexible and efficient TE generator solutions for wearable devices and sensors.[1] In particular, a flexible TE generator integrated with light-weight and comfortable textile substrates could be an enabling platform for body-heat-based energy harvesting.[2] Atomic layer deposition (ALD) is a highly controllable technique to deposit semiconducting inorganic materials directly on both yarns and textiles.[3] Combining ALD with molecular layer deposition (MLD) enables the fabrication of hybrid inorganic-organic materials with increased flexibility. We have deposited pristine zinc oxide (ZnO) and ZnO–organic superlattice thin films on a cotton textile using ALD/MLD.[4] The TE properties of our ZnO and ZnO–organic superlattice coatings are comparable to those for thin films deposited on conventional inorganic substrates. The ZnO–organic superlattice thin films moreover show enhanced resistance to mechanical strain, providing an exciting materials platform for further research towards TE/textile integration. [1] Z. L. Wang, W. Wu, Angew. Chem. Int. Ed. 2012, 51, 11700. [2] J. Bahk, H. Fang, K. Yazawa, A. Shakouri, J. Mater. Chem. C. 2015, 3, 10362. [3] G. N. Parsons, in ALD of Nanostructured Materials (Eds: N. Pinna, M. Knez), Wiley-VCH, 2012, p. 271. [4] A. J. Karttunen, L. Sarnes, R. Townsend, J. Mikkonen, M. Karppinen, Adv. Electron. Mater. 2017, in press.

J.4.5
12:00
Authors : Yury Gogotsi1, Asia Sarycheva1, Tyler Mathis1, Babak Anasori1, Zehang Zhou2, Shu Yang2
Affiliations : 1Department of Materials Science & Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, Pennsylvania 19104, United States 2Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States

Resume : Recent developments in technologies for small wearable electronic devices, such as wearable health and fitness monitors, has led to an increased demand for energy storage devices that are capable of meeting the power demands of these new devices while simultaneously being incorporated into the wearable device [1]. Herein, we report on polymer-MXene composites as potential building blocks for producing fibers and textiles that are capable of storing and delivering energy. MXenes are a large family of 2D transition metal carbides and nitrides, which show great promise for energy storage applications due to their high conductivity and intrinsic pseudocapacitive properties [2]. The MXene-polymer composites are promising candidates for flexible, ultrahigh-rate supercapacitor electrodes. These composites maximize the exposed surface area of the MXene materials which increases the accessibility of the electrolyte to the active material, as well as optimizing electrolyte diffusion during charging and discharging. Additionally, the production of hollow MXene fibers with increased transparency is possible. The versatility of MXene-polymer composite fibers sets them apart from other composite materials for the fabrication of multifunctional wearable electronic devices. References: 1. K. A. Jost, G. Dion, Y. Gogotsi, Textile Energy Storage in Perspective, J. Mater. Chem. A, 2 (28), 10776 - 10787 (2014) 2. B. Anasori, M. R. Lukatskaya, Y. Gogotsi, 2D metal carbides and nitrides (MXenes) for energy storage, Nature Reviews Materials, 2, 16098 (2017)

J.4.6
12:30 Lunch    
 
Materials For Functional Fibers 1 : Thierry Djenizian
14:00
Authors : Toshihiro ITOH
Affiliations : Graduate school of frontier sciences, The University of Tokyo

Resume : We have developed new electronic textile fabrication techniques with reel to reel micro machining and weaving integration in order to realize meter-scale large area devices for wearable and automotive applications. Conventional MEMS technologies utilizing the microfabrication equipment based on semiconductor manufacturing process, however, may not be suitable for large area MEMS devices manufacturing, because vacuum process equipment for large-area devices is too expensive, and large-area substrates are difficult to be handled and too costly. Our proposed process can offer large area devices with low cost machining tools because nano/micro film deposition and patterning area for fiber is small and automatic weaving of meter-wide textile is commonly available. In addition to the weaving, we also integrated MEMS sensors on textiles by low temperature chip mounting techniques. The developed continuous processing of fiber is composed of die-coating to form organic functional materials including P3HT, PVDF, PEDOT:PSS, PMMA, 3-D photolithography to pattern MEMS structure, chip mounting to integrate silicon devices on fibers. On our die coating system, fiber-type substrates are moved continuously with supplier and winder, and are coated by solution with the coating tool called “die”. Hundreds of nanometer thick functional films for semiconductor devices are formed by our analysis and design of die and by pressure control of the solution. Our 3-D photolithography technology for a high resolution micro process on a fiber mainly comprises the 3-D exposure module and spray deposition of thin resist film on the fiber. 3-D exposure module with long service life, low cost, narrow print gap and thus high resolution is fabricated by the wet etching of a quartz substrate and the projection exposure method. Thin 1 um thick resist is sprayed on the fiber substrates by tuning viscosity and volatility of the resist systematically. The low temperature chip mounting system for fiber and textile consists of chip mounter, dispensers and heaters. The LEDs and MEMS force sensors have been mounted on the fiber substrate and texiles. The developed automatic weaving machine can weave resultant functional fibers by defining the position of the functional fibers precisely with a linear actuator and an alignment camera. The weaving machine is 1.2 m wide and has two rapiers to weave not only polyester fibers but also functional fibers. Since cross-shaped alignment marks are patterned on the functional fiber substrates, the rapier of functional fibers grasps and moves the fiber for detecting the alignment mark for fixing the position of the fiber. Then, it weave the functional fibers between the open spaces between the warps. The large electronic textile including LED array fabric, MEMES sensor fabric, touch sensors, and solar cells is woven continuously with our looming machine, which leads to the applications including wearable and automotive applications.

J.5.1
14:30
Authors : Anja C. Pauly, Katrin Schöller, Lukas Baumann, Lukas J. Scherer, René M. Rossi, Luciano F. Boesel
Affiliations : Empa - Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Protection and Physiology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland.

Resume : The grafting of poly(hydroxyethylmethacrylate) on conventional track etched polyester membranes via ATRP[1] and subsequent modification with a light responsive spiropyran derivative is described. This method leads to photo-responsive membranes or textiles with desirable properties such as light-responsive permeability changes.[2] The controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability of caffeine (more than 1000%) upon irradiation with UV light could be achieved. We could produce membranes with either an on-off effect, or with two different, finite caffeine permeability values. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing. [1] F. Teixeira Jr., A. M. Popa, S. Guimond, D. Hegemann, R. M. Rossi, J. Appl. Polym. Sci. 2013, 129, 636 – 643. [2] L. Baumann, K. Scholler, D. de Courten, D. Marti, M. Frenz, M. Wolf, R. M. Rossi, L. J. Scherer, RSC Advances 2013, 3 , 23317-23326.

J.5.2
14:45
Authors : Byungwoo Choi, Jaehong Lee, Heetak Han, and Taeyoon Lee
Affiliations : Nanobiodevice Laboratory, School of Electrical and Electronic Engineering, Yonsei University

Resume : Recently, E-textile, an electronic device embedded in clothing or garment has attracted attention because of its various application such as motion controller, health-care device, gesture monitoring, and wireless communication. In order to develop an advanced E-textile, which possesses utility of both clothing and electronic device, the development of conductive fiber is basically necessary. So far, most previous reports for the conductive fibers have mainly focused on high performance in both electrical property and mechanical property. However, when the conductive fiber is practically applied to E-textile, the performance of conductive fiber and E-textile would get worse by water such as sweat of user, rainwater, and humid weather. In addition, E-textile could break down when doing laundry for keeping E-textile clean. To overcome these limitations, development of conductive fiber with waterproof feature is required. In this research, we present a waterproof conductive fiber with facile fabrication process. The waterproof conductive fiber is fabricated from composite of flexible polymers and metal nanoparticles. Then, the surface of conductive fiber is treated with superhydrophbobic fluorocarbon agent through Self Assembled Monolayer technique. This waterproof conductive fiber exhibits outstanding electrical conductivity (resistance lower than 1Ω/cm), mechanical durability (slight resistance change despite 10000 times of folding deformation) also, it does not get wet or electrically degrade by water or sweat because of waterproof surface feature of conductive fiber. Furthermore, the conductive fiber showed a stable response in harsh and watery conditions such as acid rain, laundry. With the aforementioned results, the waterproof conductive fiber will provide electrical conductivity, mechanical durability, and watery-stability for operation condition of E-textile for more variable applications.

J.5.3
15:00
Authors : Isabel del Agua, Daniele Mantione, Ana Sanchez-Sanchez, Usein Ismailov, Esma Ismailova, David Mecerreyes, George G. Malliaras
Affiliations : Isabel del Agua; Daniele Mantione; Ana Sanchez-Sanchez;David Mecerreyes; POLYMAT University of the Basque Country UPV/EHU, Joxe Mari Korta Center, Avda. Tolosa 72, 20018 Donostia-San Sebastian, Spain Isabel del Agua; Usein Ismailov; Esma Ismailova; George G. Malliaras; Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 13541 Gardanne, France David Mecerreyes; Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain

Resume : Functional electronic textiles have been largely made using conducting polymer coatings. Poly(3,4-ethylenedioxythiophene) (PEDOT) stabilized by polystyrene sulfonate (PSS)is a commercially available conductive formulation. Thanks to its soft nature, conducting properties, low redox potential and ease of processability, it offers outstanding performance in the field of bioelectronics. To avoid the PEDOT:PSS’s redispersion or post-process delamination, different chemicals are used with at the expense of a decrease in its conductivity. Here we present the introduction of the divinylsulfone (DVS) low temperature crosslinker in PEDOT:PSS formulation to improve its stability in humid conditions. We demonstrate that the crosslinking reaction can be performed at room temperature thanks to the high reactiveness of DVS vinyl groups. DVS does not affect the electronic conductivity of PEDOT:PSS, reaching values of 700 S/cm. PEDOT:PSS:DVS dispersion can be easily applied to textiles and used as electrodes with low surface resistivity and great biocompatibility. We also evaluate such electrodes during electromyography and electrocardiography recordings in dry and wet conditions. This new material shows great potential to make wearable and humidity stable devices in healthcare applications.

J.5.4
15:15
Authors : Tung Nguyen-Dang, Alexis Page, Yungpeng Qu, Wei Yan, Prof. Fabien Sorin.
Affiliations : Laboratoire des Fibres et Matériaux Photoniques - Institut des Matériaux - Ecole Polytechnique Fédérale de Lausanne - Switzerland.

Resume : The field of advanced functional fibers and textiles is experiencing an unprecedented development owing for a large part to recent scientific and technological breakthroughs in fiber processing. The thermal drawing process in particular, the technique used to fabricate telecommunication optical fibers, now allows for the fabrication of fibers with a large range of materials and functionalities. Flexible polymer fibers have been demonstrated to integrate metallic electrode arrays, electrically addressed semiconducting and piezoelectric domains, micro-channels, or textured surfaces with nanometer feature sizes. This provides fibers with advanced optical but also electronic and optoelectronic functionalities, with intriguing opportunities in energy harvesting and storage, fiber probes, sensing, bioengineering and advanced textiles. In this presentation, we would like to introduce the vibrant field of multi-material fibers and highlight the several opportunities for the electronic fibers and textiles community. We will in particular present the fabrication approach, materials and achievable architectures offered by this process. We will then discuss a series of recent results to highlight these opportunities: textured fibers and micro-channels for bioengineering applications (Adv. Funct. Materials, in Press), electronic fibers for touch sensing (J. of Phys. D, accepted), and highly efficient photo-detecting and temperature sensing fibers.

J.5.5
15:30
Authors : Byeong Wan An1, Young-Geun Park1, Jiuk Jang1, Jang-Ung Park1
Affiliations : School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea

Resume : Mechanical robustness, electrical and chemical reliabilities of devices against large deformations such as bending and stretching have become the key metrics for rapidly emerging wearable electronics. Metallic glasses (MGs) have high elastic limit, electrical conductivity, and corrosion resistance, which can be promising for applications in wearable electronics. However, their applications in wearable electronics or transparent electrodes have not been extensively explored so far. Here, we demonstrate stretchable and transparent electrodes using CuZr MGs in the form of nanotrough networks. MG nanotroughs are prepared by electrospinning and co-sputtering process, and they can be transferred to various desired substrates, including stretchable elastomeric substrates. The resulting MG nanotrough network is first utilized as a stretchable transparent electrode, presenting outstanding optoelectronic (sheet resistance of 3.8 Ω/sq at transmittance of 90%) and mechanical robustness (resistance change less than 30% up to a tensile strain of 70%) as well as excellent chemical stability against hot and humid environments (negligible degradation in performance for 240 h in 85% relative humidity and 85 °C). A stretchable and transparent heater based on the MG nanotrough network is also demonstrated with a wide operating temperature range (up to 180 °C) and excellent stretchability (up to 70% in the strain). The excellent mechanical robustness of these stretchable transparent electrode and heater is ascribed to the structural configuration (i.e., a nanotrough network) and inherent high elastic limit of MGs, as supported by experimental results and numerical analysis. We demonstrate their real-time operations on human skin as a wearable, transparent thermotherapy patch controlled wirelessly using a smartphone as well as a transparent defroster for an automobile side view mirrors, suggesting a promising strategy toward next-generation wearable electronics or automobile applications.

J.5.6
15:45
Authors : Usein ISMAILOV, Esma ISMAILOVA
Affiliations : Department of Bioelectronics, Ecole Nationale Supérieure des Mines de Saint Etienne

Resume : Today, wearable electronic devices combine a large variety of functional, stretchable and flexible technologies. Therefore, textiles are commonly considered to be the best substrates to accommodate electronic devices in a wearable use. Initially, commercially available solutions are exiting using metallic or carbon-based materials providing electrical functionality to the textiles. However, in many cases, such textiles fail under everyday usage conditions. In this work, we present the way of π-conjugated electroactive materials synthesis directly on textiles. This easy to apply and scalable technique enables the fabrication of highly conducting organic fabrics for an application in wearable electronic devices.

J.5.7
16:00 Coffee break    
 
Materials For Functional Fibers 2 : Luigi Occhipinti
16:30
Authors : Nils-Krister Persson, Ali Maziz, Ingrid Öberg, Isabella Christiansson Jonas Stålhand, Edwin Jager
Affiliations : Nils-Krister Persson(1); Ali Maziz (2); Ingrid Öberg(1); Isabella Christiansson (1); Jonas Stålhand (3); Edwin Jager(2) (1) Swedish School of Textiles (THS), Smart Textiles, University of Borås, 50190 Borås, Sweden. (2) Department of Physics, Chemistry and Biology (IFM), Biosensors and Bioelectronics Centre, Linköping University, 58183 Linköping, Sweden. (3)Department of Management and Engineering (IEI), Solid Mechanics, Linköping University, 58183 Linköping, Sweden.

Resume : Smart textiles is an emergent, highly cross-disciplinary field most often defined in terms of the concept of interaction – a class of artefacts having textile as a vital part with the parable being a black box taking input from its surrounding and giving output to the same. In spite of this two-way-ness most focus within the smart textiles community has been devoted to the former – creating devices for measuring and monitoring physiological signals and alike. Here we discuss the next generation of smart textiles giving output, not only taking in-going stimulus. Specifically, we report on mechanical output such as form change, strain and stress amplification. Mechanical, as compared with mere electrical, output is highly anticipated as then textiles are able to mimic movements of organs as well as of machines. As textile is the material class that perhaps is most close to man taking part in whatever human activities highly interesting opportunities open up. We discuss some different textile cases; the TATA system, thermally activated textile actuators, which are two-way, reversible all-polymer systems; and recent results on textile actuators, textutators, based on electroactive polymers. We show that all could be up-scaled and taken to industrial level production. We therefore argue that textiles are complementing other large-area, flexible electronics technologies such as printed paper electronics. For the textuators it is found that by textile processing the a) stress and b) strain from simple actuating elements could be amplified and tuned. By parallel arrangements, the exerting force is increased linearly and by serial arrangement an order-of-magnitude strain increase is achieved. By this we show the great potential of second generation smart textiles for assistive devices, fluidics, active ventilation, cilia, soft robotics, exoskeletons and artificial muscles.

J.6.1
17:00
Authors : Anshul Sharma, Catherine G. Reyes, Jan P.F. Lagerwall
Affiliations : Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg, Europe

Resume : The main areas of liquid crystal (LCs) application are electro-optical displays, temperature sensors, smart windows, reflective pigments, and high modulus polymer fibers. Recently, there has been some work done on using LCs as sensors for nerve agents and toluene vapours. [1-2] Our group has developed coaxial electrospinning as an adaptable technique to obtain fiber mats consisting of LCs as core materials and a polymer as sheath. [3-5] These fiber mats are being developed as tensile and gas sensors [6], respectively, as a new type of wearable technology. Here, we present results on non-woven mats comprising of poly(vinylpyrrolidone) (PVP) sheath surrounding a core of nematic 4-cyano-4ʹpentylbiphenyl (5CB) liquid crystal. These fiber mats can function as non-electronic sensors to detect organic vapors at room temperature and its response to various VOC’s will be discussed. [6] Additionally, we will present electrospinning as a method to get core-sheath fibers with a liquid crystal elastomers (LCE) core. The core material during spinning is a liquid crystal monomer, cross-linker, photoinitiator and solvent, and the polymerization/cross-linking is done after fiber formation. The role of spinning parameters and environment on fiber morphology and thus obtained fiber mats are studied with respect to morphological, optical and mechanical response with various techniques. References: [1] Bedolla Pantoja M. A.; Abbott N. L., ACS Applied Materials & Interfaces 2016, 8, 13114-13122. [2] Rebecca J. Carlton R. J.; Hunter J. T.; Miller Daniel S.; Abbasi Reza; Mushenheim Peter C.; Tan Lie Na; and Abbott N. L. Liquid Crystals Reviews, 2013, 1, 18-21. [3] Lagerwall, J. P. F.; McCann, J. T.; Formo, E.; Scalia, G.; Xia, Y. Chem. Commun. 2008, 42, 5420-5422. [4] Enz, E.; Lagerwall, J. J. Mater. Chem. 2010, 33, 6866-6872. [5] Kim, D. K.; Hwang, M.; Lagerwall, J. P. F. J. Polym. Sci. B: Polym. Phys. 2013, 11, 855-867. [6] Reyes C.G., Sharma A.; Lagerwall, J. P. F. Liquid Crystals, 2016, 43, 1986-2001.

J.6.2
17:15
Authors : Mr. William Serrano-García, Dr. Sylvia Thomas
Affiliations : University of South Florida at Tampa, Florida, USA

Resume : The electrospinning technique is a reliable and low cost method that has been broadly used in the fabrication of nanofibers for intelligent textiles, filters and bone scaffolds to mention some of its applications. This work is intended to use organic semiconductor polymers for electronic device fabrication that goes from diodes to sensors. These organic polymers have been noted to have excellent thermal stability, electrical conductivity, mechanical flexibility and chemical/biological functionality. The p-doped Poly(3-hexylthiophene-2,5-diyl) (P3HT) regioregular and the n-doped Poly(benzimidazobenzophenanthroline) (BBL) are studied in this work. Under a coaxial structure, P3HT as the core and BBL as the sheath of the nanofibers will form a cylindrical p – n junction. This research looks forward to expand the knowledge in organic polymeric semiconductors for efficient flexible arrays with better performance and lower power requirements as well as advancing the electrospinning technique. This process will help establish a reliable procedure for a predictable formation of the coaxial electrospinning set up for organic semiconductors.

J.6.3
17:30
Authors : Danick Briand, G. Mattana, A. Vasquez-Quintero, M. Camara
Affiliations : Ecole Polytechnique Fédérale de Lausanne EPFL-LMTS Maladière 71b P.O. Box 526 CH-2000 Neuchâtel Switzerland

Resume : We report on printed strain sensors on several meters long PET fibers for integration in textile at large scale. The sensors are made by locally inkjet printing capacitive transducers on cylindrical PET fibers used in industrial textiles. Numerical modelling of the sensors response was developed and supported the optimum design of the devices. Sensor measurements were performed for strains up to 1% and were in agreement with the model. 10 meters long functionalized PET fibers were woven with metallic interconnect fibers using large scale industrial weaving machine and resulted in a 1 m2 smart textile demonstrator. Applications are foreseen in predictive maintenance of industrial textiles or in the automotive industry. The integration of sensors into fabrics based on standard cleanroom processing of devices onto polyimide flat stripes was demonstrated [1]. Flat stripes have shown to not be ideal for weaving in comparison to the use of cylindrical fibers. Moreover, integration was performed on small area due to the production of the stripes limited to the size of silicon wafers. Here we report on the use of inkjet and aerosol jet printing to functionalize locally cylindrical long textile fibers for large area manufacturing of textile. Capacitive strain sensors were designed on PET fibers (=50 to 200 µm). The sensor consists in a stack configuration made of inkjet printed silver electrodes with in-between a parylene layer used as dielectric. When axial deformation occurs, the dimensions of the capacitor are changed resulting in a sensor response. Sensors were fabricated on 10 m long PET fibers Devices were woven to form a 1 m2 smart area in which several of these structures can be implemented in an array. Fibers functionalization and weaving process require optimization to improve the robustness. Proper operation of the fabricated sensors when applying a strain up to 1% as well as the good agreement of the results with the model were demonstrated. The process could be extended to the fabrication of other capacitive (humidity, vapour) sensors as well to the fabrication of other electronic components (resistors and transistors).

J.6.4
17:45
Authors : Maresova Eva1,2, Tudor Alexandru3, Glennon Thomas3, Vrnata Martin1, Fitl Premysl1, Bulir Jiri2, Lancok Jan2, Vlcek Jan1, Tomecek David1, Pokorny Petr2, Novotny Michal2, Florea Larisa3, Coyle Shirley3, Diamond Dermot3
Affiliations : 1 University of Chemistry and Technology, Dep. Physics and Measurements, Prague 2 Institute of Physics ASCR, Dep. of Analysis of Functional Materials, Prague 3 Insight Centre for Data Analytics, National Centre for Sensor Research, DCU, Dublin

Resume : This contribution deals with the development of the fabric-based gas sensor, which is able to detect gases and vapours at room temperature. The sensor platform is constituted from a non-conductive fabric (dimensions of the sensor are 10x15 mm). There were used two kinds of fabrics of different composition and method of production: (i) non-woven textile (70% polyester/30% polyamide (ii) and woven textile (100% polyester). To improve flexibility of the fabric-based sensor, the thermal adhesive film (Sealon Co., Ltd.) was laminated on the back side of the sensor platform. The film was applied via heated roll laminator (model Titan-110) under these conditions: an adhesive bondline temperature of 80°C for 10 sec using 100 kPa pressure. The screen printing technology was used for creation of the carbon interdigital electrodes (IDEs) (the space between electrodes 0.5 mm) on the surface of the sensor. IDEs were realized by a DEK 248 printer. The essential part of the sensor is sensitive layer based on Polymeric Ionic Liquids (PILs), namely Tetrabutyl phosphonium sulfopropylacrylate (P4444SPA) with butyl acrylate (50% molar) as a copolymer. The PILs represent a new class of polymeric materials, which possess the unique properties such as high conductivity, non-volatility, low toxicity and ability to form coatings which can actively respond to external stimuli. Therefore, they are promising materials for e.g. gas sensing. The sensitive layer was realized by application a monomer mixture on the surface of the sensor and subsequently it was polymerized by means of the LMI-6000 Fiber-Lite white light source (~200 kLux) for 30 min. In this study, we investigated the surface morphology of the fabric-based sensor by a Field Emission Scanning Electron Microscope (FESEM), model MIRA LMH. SEM images were obtained at 3kV at various magnifications. The gas sensing characteristics were determined by both DC- and AC-signals. The Sensor DC response SDC was calculated according to the formula: SDC=Rair/Rgas, where Rair is the resistance it the synthetic air and Rgas is resistance in the atmosphere containing detected gas. The results of AC-measurements were presented as Nyquist plots. The sensor response was tested to 10 ppm of four toxic gases or simulants of chemical warfare agents (methanol, nitrogen dioxide, diethyl malonate, 4-bromacetophenone). The best achieved DC-response was SDC=1.8 to 10 ppm of 4-bromacetophenone (tear gas). This fabric-based sensor with a sensitive layer based on PILs is promising for use in military, security and industrial applications.

J.6.5
18:00
Authors : Mahiar Max Hamedi
Affiliations : Department of Fibre and Polymer Technology, and Wallenberg Wood Science Centre, KTH Royal Institute of Technology, School of Chemical Science and Engineering Teknikringen 56, 10044 Stockholm, Sweden.

Resume : We demonstrate electrical valve for microfluidic systems that utilize a new phenomenon: electrowetting through textiles. We show the fabrication of valves that are fabricated using electrically conductive, and insulated, hydrophobic textiles. When the valve is closed, the liquid cannot pass through the hydrophobic textile mesh; upon application of a potential (100 - 1000 Volts) between the textile and the liquid, the valve opens and the liquid penetrates the electrically conductive mesh (under the influence of electrowetting). These valves have six noteworthy characteristics: i) They are controlled electronically (e.g., require no mechanical or moving parts). ii) They are simple and inexpensive to fabricate. iii) They can work using numerous different mesh materials. v) They operate rapidly (actuate in < 1s). v) They work with a variety of aqueous solutions including low-surface-tension liquids, and bioanalytes including blood. vi) They can easily be integrated with other thin sheet materials (such as paper) by stacking. We used these new capabilities, to demonstrate that complex electronic and fluidic ("electrofluidic") circuits can be designed and fabricated by printing, and stacking of paper and textiles. These textile-based electrofluidic circuits are capable of complex operation such as fluid logic operations or autonomous timing for controlling liquids. Paper microfluidics is currently being explored for many diagnostics application (e.g. for electroanalytical devices, protein detection, and molecular diagnostics), and yet no simple electrical solution has been presented for controlling ("valving") the flow of liquids in paper diagnostics. We, therefore, believe that electrofluidic circuits can find many uses for diagnostics.

J.6.6
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Textile Sensors, Systems, Circuits 1 : Nils-Krister Persson
09:00
Authors : John A. Rogers
Affiliations : Northwestern University

Resume : A wide range of materials and design concepts are now available for classes of electronics designed to softly interface with the human body. The same sets of physical properties – thin, lightweight construction and low modulus, elastic mechanics -- that enable these modes of use also facilitate direct integration onto compliant fabric substrates, not only as a convenient mounting location but also as a strategy for enhancing the mechanical robustness of the devices. Work presented in this talk describes the combined use of thin, ultralow modulus, cellular silicone materials with elastic, strain-limiting fabrics, to yield a soft and flexible, but rugged, platform for stretchable electronics. Theoretical and experimental studies highlight the mechanics of adhesion and elastic deformation in these systems and provide design rules for engineering artificial fabric structures with optimized properties. Demonstration examples include wireless electronics for measuring hydration state, electrophysiological activity, motion and blood oximetry.

J.7.1
09:30
Authors : Jaehong Lee, Taeyoon Lee
Affiliations : Nanobio Device Laboratory, School of Electrical and Electronic Engineering, Yonsei University

Resume : Recently, electronic textiles (E-textiles) that various electronic elements are realized in the form of textiles have attracted a lot of interests with development of wearable and stretchable electronics. To successfully achieve the E-textiles, the development of the conductive fiber with high performances is fundamentally essential. Conventional conductive fibers have been mainly fabricated by coating conductive materials on the surface of the fiber or embedding conductive fillers into the elastomeric matrix in the form of fiber. In general, such conductive fibers are hard to achieve high electrical conductivity, stretchability, and stability, simultaneously, due to the limitation in the percolation principle of conductive materials. It is very challenging to significantly advance E-textiles technology unless the performances of the previous conductive fiber is further enhanced. Here, we describe various innovative electronic textiles such as a high-performance textile pressure sensor, strain sensor, and multimodal sensor. For the development of the electronic textile, an superelastic conductive fiber, which effectively overcome the limitations of previous conductive fibers, was first fabricated using the composite of metal nanoparticles and bioinspired elastomeric fibers. The conductive fiber exhibits an excellent conductivity of 20,940 S/cm, superb stretchability of 450 %, and high stability over 10,000 cycles. By using the conductive fiber, various innovative textile mechanical sensors such as a textile pressure sensor, strain sensor, and multimodal sensors were successfully developed. The textile sensors have an unprecedented performances and can be easily integrated into fabrics, gloves, and clothes using a simple sewing method. The textile electronic devices were successfully applied to monitor human motion and operate robots wirelessly.

J.7.2
09:45
Authors : Joohee Kim, Jang-Ung Park*
Affiliations : School of Materials Science and Engineering, Wearable Electronics Research Group, Center for Smart Sensor Systems, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea

Resume : Recently, wearable electronics detecting the physiological change for the diagnosis of disease have attracted extensive interests globally. Among them, contact lens is one of the most attractive candidate for the continuous and wireless health monitoring. To realize these personal see-through, devices all device components are required to be transparent and stretchable in order to be integrated into the multiplexed sensor system including wearable soft contact lenses. However, the transparent and stretchable sensors integrated on the biomaterials are not yet been realized. In this talk, we presented an unconventional approach to form transparent, flexible and sensitive multiplexed sensors for diagnosing diabetes and glaucoma based on hybrid nanostructures using one-dimensional metal nanowires and two-dimensional graphene. Additionally, the entirely integrated sensors on the contact lens are designed to be R (resistance) L (inductance) C (capacitance) structure operating via radio frequency for wireless and real-time sensing. In this respect, power sources, associated circuitry, and interconnect electrodes are not required in this system. We further present real-time in-vivo glucose monitoring in rabbit and ex-vivo intraocular pressure sensing in bovine eyeballs wirelessly for applications in wearable electronics. The advance of these electronics using hybrid structures provides a route towards future electronics.

J.7.3
10:00 Coffee break    
 
Textile Sensors, Systems, Circuits 2 :  Yury Gogotsi
10:30
Authors : Annalisa Bonfiglio
Affiliations : Dept of Electrical and Electronic Engineering, University of Cagliari

Resume : Textile elettronics is opening an entirely new technological scenario due to the potential of nanomaterials and technologies of endowing textiles with new functionalities without significantly affecting their aesthetic and textile properties. Thanks to this feature, humans will be more integrated with the environment, wearing garments capable of a smart interaction with the surrounding ambient, which is in turn dynamically tailored to the human needs thanks to interior design products based on the proposed technology. Aiming in particular at wearable solutions, textile electronics is a viable solution for a large number of monitoring tasks, for several reasons: textiles are generally low cost, flexible, versatile materials and monitoring several bioparameters by means of devices embedded in textiles is especially attracting for the inherent unobtrusivity of these materials. Starting from a method for making a common textile fibre electrically conductive, we will give a panoramic view of several new functions, going from fibered transistors, to textile sensors. Several examples of fully textile electronic devices will be given, in particular for sensing applications. Our approach allows exploiting textile technology for fabricating a large number of sensing elements arranged in a matrix configuration while dealing with a relatively simple fabrication process that involve only sewing (embroidering) and /or stamping (printing or drop-casting) with polymeric solutions.

J.8.1
11:00
Authors : Maria Papaiordanidou 1, Seiichi Takamatsu 2, Shahab Rezaei-Mazinani 3, Thomas Lonjaret 3,4, Alain Martin 5, Esma Ismailova 3
Affiliations : 1. UMR7287
, CNRS
, Aix-Marseille University
; 2. National Institute of Advanced Industrial Science and Technology; 3. Department of Bioelectronics, 
Ecole, Nationale Supérieure des Mines
, CMP-EMSE
; 4. MicroVitae Technologies
; 5. INSERM U 1093, Cognition, Action et Plasticité Sensorimotrice, Université de Bourgogne

Resume : Wearable health monitoring devices are receiving a great deal of interest in medical applications such as monitoring human electrophysiological parameters. Transcutaneous electrophysiology is a one of the most common techniques in both diagnostics and therapy. Due to the fact that this technique is minimally invasive, it is the first method to assess pathologies of the heart and muscles. Poly(3,4- ethylenedioxythiophene (PEDOT) derivatives offer to improve long-term monitoring performance with proven biocompatibility via low skin/electrode interface impedance. Textiles coated with this material have been successfully used as electrodes in cutaneous electrophysiology. Here, we present the evaluation of PEDOT:PSS/textile electrodes in the cutaneous stimulation of muscles as well as the recording of evoked muscular activities. We demonstrate that the textile electrodes have excellent performance in surface electromyography of the lower limb and in stimulating the tibial nerve for eliciting neuromuscular responses. Their comparison with commercial electrode highlights their high performance, enhanced tolerance to noise, valuable comfort in long-term monitoring. This assessment of textile electrodes for capturing of muscular activities paves the way for the integration of conducting polymer-based textile electrodes in wearable transcutaneous electromyography or post-injury rehabilitation.

J.8.2
11:15
Authors : Marta Tessarolo 1-3, Isacco Gualandi 2, Erika Scavetta 2, Dario Cavedale 3, Beatrice Fraboni 3
Affiliations : 1 Interdepartmental Centre for Industrial Research – Advanced Mechanics and Materials (CIRI – MAM), University of Bologna, Bologna, Italy; 2 Department of Industrial Chemistry "Toso Montanari", University of Bologna, Bologna, Italy; 3 Department of Physics and Astronomy, University of Bologna, Bologna, Italy;

Resume : The development of wearable chemical sensors is receiving a great deal of attention in view of noninvasive and continuous monitoring of physiological parameters in healthcare applications. This contribution reports on the development of a fully textile, wearable chemical sensor based on an organic electrochemical transistor (OECT) entirely made of conductive polymer (PEDOT:PSS) [Gualandi, Sci. Rep., 6, 33637, 2016]. The active polymer is deposited into the fabric by screen printing processes, thus allowing the device to actually “disappear” into it. We demonstrate the reliability of the textile OECTs as a platform for developing chemical sensors for real-time detection of various redox active molecules (adrenaline, dopamine, ascorbic acid), by assessing their performance in two experimental contexts: i) ideal operation conditions (i.e. totally dipped in an electrolyte solution); ii) real-life operation conditions (i.e. by sequentially adding few drops of electrolyte solution onto only one side of the textile sensor). The OECTs response has also been measured in artificial sweat, assessing how these sensors can be reliably used for the detection of biomarkers in body fluids. Furthermore, we demonstrate the selective detection of dopamine in the presence of interfering compounds (e.g. ascorbic and uric acid) [Gualandi, Sci. Rep. 6, 35419, 2016]. Finally, the very low operating potentials (<1V) and absorbed power (~10−4W) make the here described textile OECTs very appealing for portable and wearable applications.

J.8.3
11:30
Authors : Christine Kallmayer, Malte von Krshiwoblozki, Christian Dils, Thomas Löher
Affiliations : Fraunhofer IZM; Fraunhofer IZM; Fraunhofer IZM; Technical University of Berlin

Resume : There is a trend towards ?intelligent environments? or ?ambient assisted living? where sensors and actuators that surround people or equipment are constantly exchanging information. Such environments require large area carriers for the electronic components ? textile carriers are a good solution due to the large area capability at low cost. They allow the integration of electronic systems in the environment as well as in clothing. Integrating electronics into textiles is still an emerging field. In the development of smart textiles there is a strong drive to go for integration of electronic components into textiles in high volume manufacturing. Different types of smart fabrics, interconnection technologies, and applications have already been developed. But the technologies reported so far have not yet proven to be suited for reliable mass production. Depending on the requirements of the various applications novel concepts are required for the use of conductive textiles as sensors together with the integration of conventional sensors in fabric. New yarns with well defined properties as well as special fabrication processes for the textiles are will be needed to obtain reproducible results. On different levels integration technologies have already been developed and qualified. For very small components a direct integration of chips into the yarn is possible. Larger and more complex modules require specific packages with contacts that allow the interconnection to the yarn ? e.g. crimping, embroidery, soldering, ultrasonic or adhesive bonding. Another alternative is the integration of stretchable interposers on the fabric. For all these solutions the I/O count is limited ? on the one hand due to the limitations of the fabric, on the other hand due to the necessary size of the contacts of the modules. Together the technologies nonetheless build a platform, which allows the realization of a wide range of textile applications.

J.8.4
12:00
Authors : Séverine DE MULATIER (a), David COULON (b), Roger DELATTRE (a), Marc RAMUZ (a)
Affiliations : a) Department of Flexible Electronics, Ecole Nationale Supérieure des Mines, Centre Microélectronique de Provence CMP-EMSE, F-13541 Gardanne, France. b) @-HEALTH, Europarc de Pichaury, 1330 Rue Jean René Guillibert Gauthier de la Lauzière, 13290 Aix-en-Provence, France.

Resume : Cardiovascular diseases and neurological disorders forms the majority of diseases that need periodic or constant medical attention. Such continuous monitoring requires non-invasive and imperceptible device to prevent a lack of comfort that would impede continuous wearing. For this reason, smart textiles are currently being considered as a relevant solution. Specific reliability issues related to strain during wearing and washing have to be addressed. In this work, we focus on the mechanical reliability of elementary surface mounted devices (such as passives components and microprocessor) on flexible substrates (polyethylene terephthalate and polyimide) embedded onto textile. We developed a specific experimental protocol in order to characterize the radius of curvature of the overall bent system down to few hundreds micrometers through optical measurements. At the same time, in-situ electrical characterizations are correlated to mechanical cycling in order to determine the mechanical reliability of the device. This study also investigate the mechanical behavior of the electrical interconnection between electronics components and conductive tracks. Two kind of interconnections are investigated: soldering with tin-based alloys and gluing with epoxy conductive pastes. Investigating at all levels the mechanical and electrical reliability of flexible electronic under strain points out the influence of the nature and thickness of the substrate on the overall reliability of the device. These results are therefore exploited to build a robust and sustainable solution for a comfortable and continuous monitoring.

J.8.5
12:15
Authors : Janos Vörös
Affiliations : Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Switzerland

Resume : A new class of electronic devices based on stretchable materials can interact with the soft human body in an unprecedented manner. Conductive nanowires embedded in PDMS can be processed using screen-printing or regular photolithography to create stretchable conductive leads down to 10 micrometer resolution. The process parameters, e.g. type of PDMS, nanowire concentration and arrangement allow for precise tailoring of the electrical and mechanical properties of this composite material. Stretchable and biocompatible microelectrode arrays can thus be realized that enable stimulation of intact spinal cord circuits below an injury to control the movement of the limbs aiding rehabilitation and increasing recovery of spinal-cord injured patients. [1,2] The technology also allows for creating devices with up to 500% stretchability or with Gauge factors of over 100. [3] A novel fabrication method has been developed to produce various opto-electronic components using wax-pattern assisted filtration. These devices are soft and made of biocompatible materials therefore they are ideal for in vivo applications. For example, LED and electrode arrays can be used to stimulate the brain of optogenetically modified mice or rats, respectively. [4,5] In addition, smart and passive RFID tags can be created to measure the filing level of the bladder in handicapped users. [6] REFERENCES 1. Electronic dura mater for long-term multimodal neural interfaces I.R. Minev, et al.; Science, 347(6218):159-163, 2015; 2. Stretchable electronics based on Ag-PDMS composites A. Larmagnac et al. Scientific Reports 4: 7254, 2014, DOI:10.1038/srep07254. 3. Stretchable silver nanowire-elastomer composite microelectrodes with tailored electrical properties V. Martinez, et al., ACS Applied Materials & Interfaces, 7 (24):13467–13475. 2015. 4. Fast and efficient fabrication of intrinsically stretchable multilayer circuit boards by wax pattern assisted filtration; K. Tybrandt , J. Vörös; Small 12(2), 180-184, 2016 5. Multilayer Patterning of High Resolution Intrinsically Stretchable Electronics; K. Tybrandt, F. Stauffer, J. Vörös: Scientific Reports 6, 25641 (2016); doi:10.1038/srep25641 6. www.urosense.ch

J.8.6
13:00 Lunch    

No abstract for this day

No abstract for this day


Symposium organizers
Daniel T. SIMONLaboratory of Organic Electronics

Dept. of Science and Technology, 601 74 Norrköping, Sweden

daniel.simon@liu.se
Esma ISMAILOVAEcole Nat. Sup. des Mines de Saint Etienne

Centre Microélectronique de Provence, Department of Bioelectronics , 880 rue Mimet, 13541 Gardanne, France

ismailova@emse.fr
John DE MELLOImperial College London

Department of Chemistry, South Kensington Campus, London, U.K.

j.demello@imperial.ac.uk
Tobias CRAMERUniversity of Bologna

Department of Physics and Astronomy, Viale Berti Pichat 6/2, 40127 Bologna, Italy

tobias.cramer@unibo.it