By Rachel Golan
What if your shirt could measure the weather outside and adjust to a temperature just right for you, or what if your grandmother’s socks could detect her imbalance and prevent a fall? These are our clothes of the future, and they are called smart fabrics, or e-textiles.
E-textiles are a subset of wearable technology, which includes accessories like smart watches and smart glasses. However, what makes e-textiles unique is that they consist of electronics that are incorporated into fabrics like our everyday clothes. In addition to their capability to sense, actuate, and wirelessly communicate; e-textiles are also durable, thin, flexible, and washable. This makes them a preferred option over other health-monitoring devices used in commercial and medical devices today.
The market for e-textiles is huge. According to Grand View Research, the market is projected to reach $5.55 billion by 2025 with a CAGR of 30.4%, and the medical sector will be a driving force. 1
E-textiles are divided into two main categories: embedded and laminated. Embedded e-textiles consist of a circuit that is knit or woven into the textile using electrically conductive thread. Other methods involve printing a conductive pathway on the textile using conductive ink or selectively etching away sections of a conductive textile to product pathways of higher resistance. Laminated e-textiles are circuits that are printed on non-textile substrates and embedded into a textile through sewing or bonding. For example, a circuit can be printed on a thin, flexible TPU material and then heat-pressed onto the fabric.
There are a plethora of different processes used to manufacture e-textiles depending on the application. One method developed by the National Center for Nanoscience and Technology in Beijing, China (as shown in the image above) involves covering a commercial polyester textile on both sides with Kapton tape and then using a laser cutter to cut the Kapton layer in a specific pattern without damaging the polyester in the middle.2 Nickel (Ni) coating is then deposited onto the areas of polyester not covered by tape. A cotton textile dip-coated in carbon nanotubes (CNT) is placed on top of the Ni-coated textile and a cover of thin 3M very high bond (VHB) film is added to encapsulate the completed sensor. When an external pressure is applied to the device, the contact area between the top CNT fabric and bottom Ni electrodes increases, resulting in an increase in current. This process enables the e-textiles to detect bending, pressing, twisting, and stretching, as well as acoustic vibrations from a speaker or instrument. It even has the sensitivity to detect the various components of a pulse beat wave.
E-textiles have applications in various areas of medicine, and they especially have potential in combating challenges facing the aging population. E-textiles that contain pressure sensors like the one described above can be used to manage and prevent bed sores for bed-bound patients or incorporated into compression garments. E-textiles that contain ECG, EMG, and EEG can be used to track heart rate, muscle movement and brain signal processes, respectively. Accelerometers in e-textiles allow for inertial tracking, fall prevention and detection, and sleep quality monitoring. Moisture sensors can be incorporated into e-textiles to manage incontinence issues. Finally, temperature sensors provide monitoring and feedback control in heated garment applications. They can be used in blankets that calculate whether a patient needs to be cooled or warmed based on the temperature of the environment, as well as in surgical scrubs to cool a surgeon during surgery based on his/her body temperature. The potential applications of e-textiles are endless.
Do you have a novel idea for an e-textile that you want to bring to fruition? Root3 Labs is here to assist with any of your e-textile needs, whether that means selecting and evaluating a sensor for a specific application or designing and fabricating an entire smart textile device. Let us know how we can help with your next project. After all, even the smartest garment cannot outsmart us!
Cited Sources and Images:
[1] Smart Textile Market Size Worth $5.55 Billion By 2025: CAGR: 30.4%. (2019, March). Retrieved October 14, 2020, from https://www.grandviewresearch.com/press-release/global-smart-textiles-industry
[2] Liu, M., Pu, X., Jiang, C., Liu, T., Huang, X., Chen, L., . . . Wang, Z. L. (2017). Large-Area All-Textile Pressure Sensors for Monitoring Human Motion and Physiological Signals. Advanced Materials, 29(41), 1703700. doi:10.1002/adma.201703700
Additional Resources:
Brown, P. (n.d.). The Future of Healthcare May Reside in Your Smart Clothes. Retrieved October 14, 2020, from https://www.mouser.com/applications/healthcare-may-reside-in-smart-clothing/
Yang, K., Isaia, B., Brown, L., & Beeby, S. (2019). E-Textiles for Healthy Ageing. Sensors, 19(20), 4463. doi:10.3390/s19204463
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