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Functional Fabrics: Adaptive, Flexible Engineering Computing Platforms of the Future

Functional Fabrics

Functional textiles are fabrics with a set of integrated functions of controlling or adjusting according to its application. Such textiles are usually produced with a focus on function rather than on aesthetics. Smart textiles are characterised by functionality, versatility, compatibility, flexibility and interactivity. Functions could include temperature regulation, humidity control, health monitoring, sports training, position tracking, protection clothing, abrasion resistance, anti-bacterial properties, moisture absorption, quick-drying functions, and many more.

The use of functional fabrics is versatile and becoming common in a number of industries such as automotive engineering, aerospace, aeronautics, architecture, healthcare, construction engineering, military and security.

*Functional textile materials are defined as those materials that do not have any “smartness” as such, but in many cases form a basic component of a smart textile (system), e.g., electroconductive textiles or optical fibers.

Why textiles?

All of the human experience is in direct contact or very close proximity to textiles structures in various forms. Clothing. Automotive interiors. Protective Equipment. Shoes. Acoustic covers. Filters. Seats. Inflatable structures. Composites.

Textiles are a foundational manufacturing technology that has enabled shelters, creative expression, composites, medical implants, high speed communication, and even inspired the earliest computers [1], kicking off the information age.

Fiber and textile-based devices are gaining traction in the flexible electronics world as a versatile form factor to serve a wide range of applications, due to their mechanical attributes, feature sizes, ubiquity, and ability to conform to the human body. Advances in materials science coupled with adjacent developments in communication technology (e.g. 5G communication) are synergistically converging to usher in a new breed of fibers, yarns, and textiles as integrated, networked systems for a wide range of high value applications across sectors from defense to healthcare. The market for electronic textiles is projected to reach $2 B/year by 2028 [2].

DigitSole socks smart textile
Digitsole, a startup from France, integrates electronics into footwear to offer consumers more functions. Run Profiler are connected insoles dedicated to measure, analyze and improve running performance. Equipped with an activity tracker, they are more precise and complete than a wristband or a connected watch, due to which the Run Profiler is able to analyze sports performance in 3D and real-time. This data helps improve performance, manage fatigue and detect the risk of injury.
Digitsole, a startup from France, integrates electronics into footwear to offer consumers more functions. Run Profiler are connected insoles dedicated to measure, analyze and improve running performance. Equipped with an activity tracker, they are more precise and complete than a wristband or a connected watch, due to which the Run Profiler is able to analyze sports performance in 3D and real-time. This data helps improve performance, manage fatigue and detect the risk of injury.

Universities, industry, funding agencies, technical societies, and government agencies worldwide are forming coalitions to drive this revolution forward – an excellent example of this collaboration is the Advanced Functional Fabrics of America (AFFOA) Manufacturing USA Institute headquartered in Boston, MA which is heavily funded by industry, government agencies, and universities to create a fabric-based revolution in computing. Its’ membership is diverse and includes colleges and universities such as MIT, University of Central Florida, North Carolina State, Clemson, and Drexel University as well as industry partners including Tesla, Airbus, Flex, Nike, 3M, Steelcase, Adidas, Under Armor, Goodyear, VF Corporation, and Saint-Gobain.

Product development challenges or why aren’t you wearing a smart fabric today?

A number of technical and commercial challenges lie ahead to realise the full promise of “smart” textile-based devices. From an engineering mechanics perspective, textiles are multi-scale, extensible structures – they can be nanometers or kilometers in length. Textile structures can be produced with relatively higher levels of control over local morphology than achievable in 3D printing processes, where microstructure formation is governed by the complex kinetics of melting & solidification.

Furthermore, advances in electrospinning, fiber drawing, extrusion enable fabrication of unique fiber and yarn materials with highly desirable sets of intrinsic properties. However, system integration remains a major challenge.

Functional fabric devices often rely on some combination of mechanical, electrical, thermal, and optical phenomena to achieve their function. The community is quite fragmented and multidisciplinary – no single company or university has all of the expertise needed to realise a smart fabric product.

A collaborative, approach bridging disparate communities – electronic hardware manufacturing, textile manufacturing, materials science, fashion design, computer science – is needed to advance smart textile devices from science projects to mass market production and customisation.

Performance prediction & design optimisation

Much of textile engineering relies on trial-and-error design approaches, which are costly and time consuming. Functional Fabric devices are a perfect exemplar for the unprecedented levels of sophistication and complexity inherent to today’s engineered products. Multidisciplinary design optimisation across mechanical, thermal, optical, and electrical phenomena of a textile system’s performance has excellent potential to shorten time-to-market and reduce development costs of translating concepts and prototypes into scalable, production-ready solutions.

Current textile-focused computer-aided design & manufacturing software offers high fidelity aesthetic visualisation of fabrics and specification of manufacturing commands at the stitch level but does not give performance prediction of how a fabric will perform when manufactured.

Classification of functional textiles by Taiwan Textile Research Institute.

Generative design is the concept of leveraging optimisation algorithms (e.g. shape and topology optimisation) coupled with high performance computing to rapidly explore a design space given a set of objectives & constraints [3]. For a class of materials as complex as textiles, generative exploration of design space to find the most promising combinations of material and spatial arrangement to meet an end use performance specification will be a key accelerator of new product.

Manufacturing

The electronics and textile manufacturing industries could not be more different. Textile fabrication involves manual cut & sew processes, introducing significant operator error to the processes, whereas electronics manufacturing processes are highly automated with far tighter tolerances. As such, allowable tolerances are orders of magnitude greater in apparel products than they are for electronic hardware.

Standards, testing, & certification

As any technology matures, industry standards are essential to ensure quality, interoperability, safety, and performance of new products or processes. Standards enable innovation in any space through establishing the methods used to evaluate and compare new products on a common, objective basis across an industry.

American Society for Testing and Materials (ASTM), American Association of Textile Chemists and Colorists (AATCC), and ISO have many standards pertaining to textile, paper and pulp products. Existing textile standards tend to focus on endurance, e.g. testing for laundering cycles or breaking strength. While these are certainly important, there are currently no dedicated standards even the most basic elements of smart textiles, e.g. interconnects.

The functional fabrics community is coming together as we speak to develop a new body of standards for the future of the industry, segmented by application area – e.g. heart rate monitoring, electrical resistance measurement, perspiration composition measurement, strain measurement, fabric heat storage/release capacity.

Some example applications

Heating, ventilation, and cooling account for 13% of the United States’ energy usage [3]. What if thermal adaptive clothing could control the microclimate around each individual? Enabling building managers to relax their heating/cooling requirements, and thereby reducing HVAC energy consumption. Kestrel Materials, an OtherLab spin-out company is commercialising thermally adaptive garment technology based on textile bimorph structure with strategically mismatched coefficients of thermal expansion – no electronics required.

In the world of haptic feedback and augmented/virtual reality, the Teslasuit integrates haptic feedback, motion capture, and climate control into a garment form factor, allowing users to touch and feel virtual environments over the entire body. The haptic suit tracks the wearer’s motion at a high sampling rate and can deliver precise sensations of touch, impacts, rain, and wind through small electrical impulses modulated through an onboard computer. The suit is washable, wire free, and compatible with existing electronics.

The Capacitive Touch Sensor (CTS) is a gesture sensitive functional textile touch-pad interface for physical devices. The CTS is produced as a single piece of fabric requiring only two electrodes to connect it to a microcontroller. The CTS offers a solution for a flexible touch interface with consistent location detection, responsiveness, comfort and unobtrusiveness.
The Capacitive Touch Sensor (CTS) is a gesture sensitive functional textile touch-pad interface for physical devices. The CTS is produced as a single piece of fabric requiring only two electrodes to connect it to a microcontroller. The CTS offers a solution for a flexible touch interface with consistent location detection, responsiveness, comfort and unobtrusiveness.

Weaving it all together

Textiles are ubiquitous and have been with humans for thousands of years. The earliest computers in fact were inspired the punch card programming on the Jacquard loom, which inspired Herman Hollerith in the 1890s to found company that became International Business Machines (IBM). Now, textiles are poised to be the pervasive computing platforms of the21st century.

The built world today is not formed from any singular form of manufacturing technology, but a combination of multiple technologies. The same will be true for functional fabrics as well.

"Materials are often the rate-limiting step across a wide range of end use applications, and I think Matmatch is doing interesting work to enhance the visibility of materials data. I'm truly excited about the upside for soft, flexible, augmented materials and appreciate the opportunity to share that passion with the broader materials community."
Daniel Christe, Innovation Advisor, Elsevier
Daniel Christe
Innovation Advisor, Elsevier

Further reading:

Check out these projects by the Fraunhofer Institute for Reliability and Microintegration IZM:

Syduzzaman, Patwary SU, Farhana K, Ahmed S (2015) Smart Textiles and Nano-Technology: A General Overview. J Textile Sci Eng 5:181. doi: 10.4172/2165-8064.1000181 [PDF]

Xiaoming Tao (2016) Handbook of Smart Textiles. Institute of Textiles and ClothingHong Kong Polytechnic UniversityTai Po, Hong Kong. doi: 10.1007/978-981-4451-68-0 [PDF]

References:

[1] Essinger, James (2004). Jacquard’s Web: How a Hand-Loom Led to the Birth of the Information Age. Oxford: Oxford University Press
[2] E-Textiles 2018-2028: Technologies, Markets and Players.
[3] Generative Design.

*This article is the work of the guest author shown above. The guest author is solely responsible for the accuracy and the legality of their content. The content of the article and the views expressed therein are solely those of this author and do not reflect the views of Matmatch or of any present or past employers, academic institutions, professional societies, or organizations the author is currently or was previously affiliated with.

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