E-Textiles, one of the major sectors contributing to ‘Smart Wearables’, broadly includes development, characterisation and application of conductive textiles such as sensors, actuators as well as power sources. There has been novel and interesting research work reported across the globe in this area. Many of such research spin out of the Laboratories, often named as ‘FabLabs’ in the Universities. This article, the second in the series, will discuss about the role played by Research Labs in smart textiles and wearables.
Research groups are working to explore the possibilities right from the level of polymers, fibres, yarns, fabrics till apparels and accessories. Some such research groups include laboratories of the Universities in the US like Wilson College, NCSU, Georgia Institute of Technology, Cornell University, University of California Berkeley, Penn State University, Drexel University, Stanford University to name a few. The United Kingdom is also home to such research groups – University of Bolton, University of Southampton, Imperial College of London and others. Concordia University, Canada, University of Boras, Sweden, ENSAIT France, University of Wollongong, Australia and Ghent University, Belgium represent others in the world map for research in E-textiles. The research in E-textiles includes utilisation of conductive polymer, fibre, yarn and fabrics or conductive inks and coatings. The IDTechEx research shows the distribution of e-textile players in 2019.
Research and development in Smart Textiles no doubt existed for quite a long time, however, it has gained momentum in the recent past only. No wonder we are witnessing two of the premier institutes of the world come together to contribute with their expertise in this field – Massachusetts Institute of Technology (MIT), Cambridge and Fashion Institute of Technology (FIT), New York. Every year, a team of students from both the institutes team up to work on projects in the area of Smart Textiles. Biodegradable footwear, active textiles are the deliverable of one such joint project. Furthermore, Media Lab at MIT has taken up several research projects in Smart Wearables specific to E-textiles. Extensive research has been conducted here and is ongoing for embedding or integrating sensors into textiles in the form of woven or knitted garments.
Centre for Functional Fabrics (CFF) at Drexel University is one of the research centres in the field of functional fabrics research which is mainly focusing on developing smart wearable out of 3D knitted textiles. Prof. Genevieve Dion is spearheading the research activities of the Centre which took up its shape in the year 2012 initially through a seed funding received from a leading textile manufacturer. They have the infrastructure for development of 3D knitted fabric along with simulation, modelling and design facilities required for advanced manufacturing of textiles. Drexel University through CFF is also a key stakeholder of the Advanced Functional Fabrics of America (AFFOA), established by the US Department of Defense. The Pennsylvania Fabric Discovery Center (FDC) has been established through this collaboration of CFF and is also managed by Prof. Dion. It is supposed to facilitate advanced textile manufacturing in Pennsylvania and the Mid-Atlantic Region.
Prof. Dion is one of the few researchers who holds the opinion that textiles in the wearable technology field has a lot more than functionality with comfort and aesthetics being equally important and soon to be sought after criteria for developing smart clothing. That might be the reason for her to be recognised as a Design Scientist. A project partially funded by Drexel University Maternity- Smart Fabric Belly Band, to Monitor Uterine Activity and Assess Fetal Well Being is under progress to develop belly band for mother and fetus health monitoring. Conductive yarns are integrated through knitting and the product uses a passive radio frequency identification tag. The idea is to provide mobile solutions for monitoring contraction and respiration monitoring during pregnancy by reducing bulk through utilisation of battery less wireless sensor.
Pictorial representation of Smart Bellyband
Another deliverance of students’ project at CFF is smart band developed by incorporating biomedical sensors and actuators in knitted fabric which tracks the wearer’s respiratory rate, activity and temperature. The band is also supposed to utilise Bluetooth Low Energy to monitor potential exposures, in a similar manner as mobile apps work for contact tracing functions. This project, though taken up to address the COVID pandemic needs, may also turn out to be helpful for elderly population. The project received IEEE Philadelphia Section Merrill Buckley Jr. Student Project Award for their paper presentation. It was also recognised among the top 14 projects worldwide by the IEEE communication society.
GemTex Lab at ENSAIT France worked on a 4-year project named CONTEXT – CONnected TEXTiles for Communications Around the Human Body. The focus of this research project was to incorporate radio frequency technologies in smart textiles along with establishment of wireless communications between objects around the human body. The research also aimed to enable reducing the size of the antenna used for such communications. This project was led by Prof. Cedric Cochrane. The Lab has delivered several projects like Camille 3D, Component, Mapicc 3D to name a few. Research group at GemTex has utilised smart textiles for autonomous ambient lighting applications through its project Luminoptex. The organic light-emitting diodes (OLEDs) are integrated into the fabric, which will be powered autonomously through energy harvesting. The energy available within a building in the form of an electromagnetic field is harvested and then stored within batteries or supercapacitors. This energy is then used for autonomous lighting of OLEDs. The applications include automotive interior lighting, signal boards, decorative upholstery and so on.
Prof. Vladan Koncar, at the GemTex Lab led a similar project Liteva (acronym for Lighting Interieur TExtile for Autonomous Vehicle). The main aim of this project was to develop multifunctional textiles that can enable active safety of vehicles, through colour and light sensory. The project had four major objectives to be achieved through development of a textile based interior capable of displaying a dynamic light signal, ensuring a visible alert under all circumstances, enabling display of complex messages and to answer the specifications required in an automobile as safety measure.
The ‘Farm to Lab’ initiative led by Dr. Javad Foroughi at University of Wollongong– Intelligent Polymer Research Institute (IPRI) under the umbrella of Smart Garment Project, was funded through New South Wales Tech-voucher program and Bluey Merino, in 2014, which aims at utilising an array of antenna embedded in fabric to harvest energy from a probing signal. The harvested energy is thereafter used for communication. The information communicated can be used to monitor and track the status and distribution of mining personnel in locations where the Global Positioning System might not work. This can also be used for personnel working in other hazardous work environments. This does not use the traditional tag system, which otherwise can be tampered, for tracking but integrates the information into the yarns which also helps in restricting counterfeit products e.g. it helps Australian producers to differentiate their original merino wool products from imitation ones.
The university’s repository also suggests that researchers are actively striving to come up with wearable technology with a textile base in the form of sensor, actuator and power generator. One of the 2019 PhD thesis reports on development of artificial muscles out of fishing lines and sewing threads which are cost-effective, thermally operated superlative actuators. The artificial muscles developed were attempted to be embedded in smart textile structure to provide a practical application with human interference. Another 2020 doctoral thesis highlights the fabrication of piezoelectric fibre for integration in textiles to form varied structures- wovens, knits, braids, etc., to be used as self-powered sensors for applications such as power generator, health and motion monitoring, air and water sensor.
The Centre for Textile Science and Engineering (CTSE) led by Prof. Lieva Van Langenhove, at Ghent University has been involved in several projects related to smart textiles since very early years of research in this area. They are one of the collaborators for the project PROeTex. PROeTEX-PROtection E-TEXtiles, is a European project which mainly focuses on development of wearable textile systems for rescue workers and firemen. Another involvement was through project – HYDRAX, a consortium that aimed at developing a textile-based thermal flux meter which could be used to detect temperature differences, such as in fire fighting suits, or in sports and medical textiles or in geotextiles. All4Rest, a European SME driven project, involving 13 partners from Belgium, Spain, Germany, the Netherlands and Portugal, aimed at improving the sleep quality of people. It involved conducting research to develop heatable/ cooling textiles for thermal comfort improvement. It further led to development of textile integratable sensors to monitor body movement and temperature. Few other projects taken up by the centres were Magnum Bonum and Creation. The centre also has taken initiatives for knowledge sharing and technology transfer to enable the lab research to reach the market as a commercial product/process. SmartPro, Smart@fire, Smart Textiles Salons, COLAE, SYSTEX, Tritex are few of the projects which took up initiatives in this regard.
Wilson College of Textiles, North Carolina State University (NCSU), is one of the hubs for ongoing research in the field of smart textiles, E-textiles in specific. The research studies conducted include a complete hierarchy of textiles i.e. from fibre to fabric and garment as well. Prof. Xiangwu Zhang and his team have developed functional nanofibers to be integrated into rechargeable batteries and supercapacitors. They have been found to have long-life with high performance with the added advantage of being compact and lightweight. This is going to address the increasing need for high-performance electrochemical power sources required by an E-textile based smart wearable product. Presently the group is working on various types of flexible energy-storage devices.
Schematic representation of high-performance nanofiber-based batteries and supercapacitors
Prof. Wei Gao and Prof. Eunkyoung Shim at NCSU teamed up to develop a strain sensor and an energy-storage unit prepared out of a stretchable fabric. The strain sensor is fabricated through graphene surface coating on the fabric which offers electrical conductivity and senses local deformations. In similar manner, the energy storage unit also relies on graphene coatings and laser patterning which can sustain stretching and twisting of fabric substrate, to certain limits.
The graph below depicts quite interesting correlation between the research activities (mapped through publications) and sales figures (mapped through sales) for the Smart Textile sector (Inclusive of E-textiles) and for Wearable Electronics (in general). The matching pace of sales with research since 2010 is a testimony to the ongoing popularity of smart textiles and smart wearables.
Source: Plenary talk, Prof. Vladan Koncar, International Conference on Functional Textile and Clothing 2020, held at IIT Delhi, India, in February 2020
The countries leading the commercial space in this sector is depicted In the World Map below and it is inspiring to find correlation between countries which are into academic research with countries which are in commercial player list, for smart textiles. The research if explored round the globe being conducted at various Laboratories as an integral part of universities and other Academics, are quite significant.
The challenge which lies beyond this is its conversion to a product, commercialisation and upscaling of the same. While the developed smart wearables at lab-scale need to offer reproducibility and standardisation for large-scale production by a manufacturer, they also need to offer reliability and durability from a consumer perspective. Further the evaluation and characterisation of smart textile ensemble inclusive of E-textiles is yet to be standardised for which various standardisation bodies are attempting to bring the experts from multidisciplinary fields (Electronics, Textile, Material Science, etc.) to one platform and enable the formulation of standards. Currently, these challenges are being attempted by commercial players in collaboration with various Academic and Corporate R&D Teams. ProeTex is one such example of collaborative work in the area of Smart Textiles where 23 different entities from 7 different countries and 4 different sectors came together and have successfully delivered smart garments for emergency disaster personnel e.g for Ensemble for firefighting personnel. However, as on date, one still awaits to see maximum conversion of the research based smart prototype to commercial smart textile product.