The Innovation, Industry, and Future of the Smart through Microelectronic Integration

Mate 340 Johnson-Glauch Maxi von Welczeck

Abstract

The following document serves as an intensive literature review on the advanced textile(E- textile) and smart textile. This review will discuss and discover the advanced and smart textile’s origin and history, innovation and use, and future use, and focus heavily on the industry.

2 Table of Contents

Introduction 1.1 Definition of an Advanced Textile 1.2 History and Origin 1.3 Applications

Main Findings 2.1 Passive/Active Smart 2.2 Specific Materials and Processing 2.3 Manufacturing and Design 2.4 The Future of the Fabric Industry

Gap in Literature 3.1 Durability 3.2 The Problem of Integration 3.3 Experimentation

Conclusion 4.1 Summary of Finding 4.2 Future of Smart Textiles

3 Introduction

1.1 The Definition of an Advanced Textile

The advanced textile also known as the E-textile is the integration of microelectronics into textiles and fabrics. However, before understanding the science behind the advanced textile, it is crucial to understand its foundation, which is based on the smart textile. Textile innovation has gradually increased over the years but now comes a time where textiles can become so much more than just garments of clothing. Smart textiles are described as materials that are able to react and adapt to their environment by their textile structure. These textiles respond to thermal, electric, chemical, and other outside forces. The integration of microelectronics will maximize the textile to make the best interface between the technology and its user. The new emerging industry of the advanced textile will serve many benefits. Smart textiles once manufactured in combination with a piezoelectric material, form an advanced textile or adaptive garment that will react and adapt to a person needs through a technological interface. Advanced textiles are now used in healthcare, streetwear, athletic, and military industries. The development of smart textiles and advanced textiles offers numerous amounts of benefits for many applications and industries. The development and origin of the smart textile is further explored in the next section.[1]

1.2 History and Invention of the Smart Textile

The first smart textile was invented in 1989 in Japan which was a that had a memory shape effect complex. This material was the first product to offer intelligent materials in textiles. Although there were similar products in the 1960s and 1970’s like polymeric gels, these materials were not on the same intelligence spectrum as the memory silk because they were not integrated in textiles. The smart textile since the 90’s has been further advanced through the integration of microelectronics.[1]

1.3 Applications

In the barest meaning of a textile, it is a material that is used as a garment for warmth or cooling of the body. Now that the civilization is moving into a world of microelectronics and technology at our fingertips, the next logical step is to integrate technology into the textiles themselves thus producing the advanced textile. The integration of technology into the interface of the textile will allow the user for more user-friendliness, user-empowerment, and more efficient services support[1]. In some aspect’s smart watches, or google glasses show this relationship between user and technology friendliness, however the smart textile will take this relationship to the next level.

Despite that textiles are used primarily in the clothing industry the smart textile offers many advantageous characteristics and qualities to other industries. This can be seen in Table I from Ambient Technology by S. Jung, and C. Lauterbach.[1]

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Table I: Technical Textiles, Application, and Microelectronic Functionality [1]

5 Smart textiles can be used in hometech such as walls, floors, buildings, roads, mobil techs, sports tech etc. There is a wide range for smart textiles. This report will focus on wearable advanced textiles, therefore focusing in on the sporttech, MedTech, and industries. When focusing on these industries, the advanced textile will also be referred to as an adaptive garment or E-textile. The adaptive garment is great for temperature regulation, and independent of the wearer’s activity. These materials enable for comfort during sweating, rain and wind permeation, thermal regulation, self-cleaning, and lastly biological and chemical protection.[1]

Main Findings

2.1 Passive/Active Smart Textiles

In discussing smart textiles an important distinction to make is that of the passive and active smart textiles. The passive textile can only sense the environment whereas the active smart textile can sense the environment and then react to its environment, through their sensor function.

Passive smart textiles are known as the first generation of smart textiles. What defines the passive textile is that it will react to its environment, but it will not adapt to the environment. For example, a cooling fabric. This type of fabric can cool your body however after it has cooled your body and regulated your temperature, it will not actively cool itself back to normal. So, after its used the material will warm. A better way to look at this is like an ice pack; an ice pack may cool you down temporarily but overtime the ice pack will heat up and lose its function of cooling as it was not be able to adapt to the environment being your skin and the outside atmosphere. The passive smart textile is more advanced than the traditional textile however it is less evolved than that of the active smart textile.[2]

Now, an active smart textile will react to its environment and respond by either changing shape, storing and regulating heat, or other functions[3]. This reaction and the adapting to its environment serves as a beneficial trait when integrating microelectronics[3]. Active smart textiles use actuators and sensors which utilize electricity to perform their proper environmentally induced responses. [3]

2.2 Specific Materials and Processing

The advanced textiles industry is composed of one, the smart textile and two, the microelectronics. In this literature review, intelligent wearables are of utmost interest. In this two-part system it is important to, one look at the integration of the technology, and then two the actual garment, so that it is comfortable and good to wear.

6 For the microelectronics integration mainly, piezoelectric materials are used. Typical piezoelectric materials that are used are lead zirconate titanate, PVDF, and P(VDF-TrFE) [4]. Piezoelectric materials are used for energy harvesting and sensor applications thus they can be used to sense motion and other responses by the human body. Polymers make great piezoelectric materials, specifically polyvinylidene fluoride polymer and barium titanium oxide ceramic because of their great flexible piezoelectric generators. These materials are then electron spun into nanofibers. The nano serve a crucial part in developing the advanced textile. That information gathered by the sensor of the piezoelectric material is then transferred through the conductive nanofibers to cause the smart textile to react and adapt to the bodies changing conditions. This offers great advantages in terms of structural health monitoring systems, self-powered sensors, and lastly harvest the energy from body movements cheaply.[4]

The electro spun nanofibers are used in smart textiles for moisture management, water proofing, thermal regulation, personal protection, sensors, wearables, and medical care[4]. The small nanofiber membranes are woven to be small conductive fibers that enable the transmission of electrical signal to the piezoelectric materials. This creates the seamless interface between the technology and the textile. The small conductive fibers are manufactured via CVD (chemical vapor deposition), spinning, drawing, electrospinning, and drawing[4]. Research has found that the smaller the diameter the better it will perform as a conductive material. Figure 1 depicts this relationship.

Figure 1: Effect of fiber diameter on surface area [4]

When focusing on the textile itself, the important qualities and desired mechanical properties are low initial Young’s modulus, and a low friction coefficient which makes a soft, smooth, and comfortable material. An interesting new study which was influenced by the original smart textile silk, examines Yamani silk-like regenerate B.Mori silk fibers(RBSF’s) [5]. This is new a type of smart active textile. This material offers great extensibility and modulus compared to natural

7 Yamani silk. The unique qualities that RBSFs possess are its ability to react and adapt to force and temperature stimuli for smart textiles. This silk derived from animal silk which has great mechanical properties such as high combined modulus, strength, and extensibility. These properties make for a great smart textile base for advanced textiles.[5]

2.3 Manufacturing and Design

A method of making these smart textiles is through treated conductive fibers. In this approach the smart textiles are woven fibers that can be functionalized by electronics. These fibers can then be further electricized by coating them by galvanic substances or metallic salts, or metals[6]. The processes that are used to manufacture these materials are electroless plating, evaporative deposition, sputtering, and coating the polymers. Lastly the smart textile can be made through crossing to make a transistor in Figure 2.[6]

Figure 2: -Based Transistor [6]

The smart textile, which also can be defined as E-Textiles can also be produced through making conductive fabrics. This is produced through together conductive yarns. The issue here is making the material comfortable to wear while keeping its electrical properties.

There are many different fibers used. A quick summary of the production of several different materials and production methods are shown in the table below.

8 Table II: Processing of Nanofibers and their Applications [4]

Manufacturing the advanced textile takes intertwining the conductive fiber and the processing piezoelectric material, or chip module for adaptive reading. These chips are mounted on RFID tags which is then further interconnected between a layer of conductive adhesive, anisotropic conductive adhesive or non-conductive fibers. Then finished off with either an aluminum or PET laminate[7]. This can be seen in the Figure 3 below.

Figure 3: Manufacturing the module chip with conductive fibers [7]

9 2.4 The Future of the Fabric Industry

The fabric industry is an ever-expanding industry. Fabrics and textiles are used in many ways in our daily lives, form clothing, to window blinds, and even children car seats. In 2000 the world saw 16.7 million tons of technical textiles and nonwovens be manufactured and that grew by 5% in one year[8]. Now in 2020 it is expected that the world will reach up to 42.2 million metric tons of technical textiles produced for the year[9]. The textile industry is a growing industry and now incorporating microelectronics into smart textiles will further the production and growth of technical textiles. [8,9]

Gap in Literature

3.1 Durability

Another issue with microelectronics in smart textiles is its durability. A smart textile may be used a lot, and through environmental conditions and daily use the material system may not be able to perform that well for a long time. Investigating how the advanced textile is affected over long periods of time is crucial in determining the smart textiles and the microelectronics long term durability.

3.2 The Problem of Integration

The process of integrated microelectronics can be expensive and there is a greater issue of long-term health effects. If someone were to wear a smart textile that had microelectronics for a knee injury that would stimulate the knee with electronic pulses, how would the effect of the electronics and metal being in contact with your body for so long affect it. Time and research will only tell. [10]

3.3 Experimentation

To better understand the gap in literature experiments should be conducted to better understand the advanced textiles. To understand the durability of the advanced textile the product should be worn and put in harsh conditions. An experiment that could be performed is to use an advanced textile arm sleeve that monitored your vitals and other attributes, while the smart textile part adapted to the cold or warmth to perform more efficiently. This product would be tested a variety of people like average consumers, doctors, athletes, and military. This consumer should be exposed to physical exercise, changing environments such as rain and high heat, and lastly physical force. By examining how the product reacts to pressure, change in environment, and motion over duration of time then the long-term durability of the product can be determined.

10 In addition, the long-term effects of advanced textiles should be studied. Outside of simulations, perhaps animal testing could be used for animals with shorter life spans. A similar advanced textile product like a sleeve from the first experiment would be worn by the test subject and then would be analyzed for the health effects on the test subject over their lifespan. This experiment should be done only with the best interest of the animal at hand, so if large effects are shown prematurely, then those tests should be shut down early. However, with where advance textiles are currently, there is little reason to believe that the advanced textile would hurt the animal. This testing would be a precautionary measure in order to better understand how the advanced textile will affect humans over time.

Conclusion

4.1 Summary of Findings

Smart textiles in combination with microelectronics form advanced textiles which will be the next generation of clothing, fashion, MedTech, etc. These materials are made via the combination of piezoelectric nano fibers and smart textiles, typically made from animal . The advanced textile is an adaptive garment that will allow for seamless integration between technology and its user, thus producing a product that can react and adapt to the user’s needs on demand. More research must be conducted on the long-term durability of the advanced textile system, and the long-term health consequences of the advanced textile product. The textile industry is booming, and the progression of advanced textiles is crucial for the development of the textile industry.

4.2 Future of Smart Textiles

The next steps are to make environmentally friendly products. To produce advanced textile products more efficiently, and to gather more information on the health impact on people. It will be important to discover the lengths at which materials can possess electrical properties so that more efficient and seamless interface between the electronics and user can take place.

11 References

[1] C. Lauterbach, S. Jung, et al. Ambient Intelligence. Springer, 2005, pp. 31-47.

[2] T, Dias, E.D, Electronic Textiles: Smart Fabrics and Wearable Technology, Elsevier Ltd . 2015.

[3] H. de Vries, R. Peelings, Predicting Conducting Yarn Failure in Woven Electronic Textiles, 2014, pp. 2956-2960

[4] F. Mokhtari, Z. Cheng, R. Raad, J. Xi, J. Foroughi, Piezofibers to smart textiles: a review on recent advances and future outlook for wearable technology, Journal of Material Chemistry A, pp. 135-295, May 2020

[5] Wenwen Zhang and Chao Ye, “Tensan Silk-Inspired Hierarchical Fibers for Smart Textile Applications,” ACS Nano, ACS Publications, pp. 6968-6977, 2018. [Online]. Available: ACS Nano, https://pubs-acs-org.ezproxy.lib.calpoly.edu/. [Accessed November 19, 2020].

[6] Journal of Engineering, Researchers at Hong Kong Polytechnic University Report Findings in Materials Science (Smart Textile-Integrated Microelectronic Systems for Wearable Applications), 2019, pp.1877

[7] P. Domique, P. Crego, E.D, Wearables, Smart Textiles & Smart Apparel, Elsevier Ltd, 2018.

[8] M. Rashid, “World Technical Textile Consumption to Reach 42.2 million metric tons by 2020,” Textile Today, p. 1, October 27, 2016. [Online]. Available Textile Today, https://www.textiletoday.com. [Accessed November 17, 2020].

[9] N. Yilmaz, Ed., Smart Textiles: Wearable Nanotechnology, Scrivener Publishing LLC, 2018.

[10] M.Stoppa, and A. Chiolerio, “Wearable Electronics and Smart Textiles: A Critical Review,” PubMed, pp. 957-992, July 2014

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