Flexible Textile Structures for Strain Sensing Applications

Abstract

The strain sensors are the sensors widely used for many applications, and the measurement of change in strain is called as strain sensors. Conventional metal- and semiconductor-based strain sensors are rigid, fragile, and opaque, restricting their applications in wearable electronics. Flexibility, stretchability, biocompatibility, and comfortability are all on the wish list for future wearable electronics. In recent years, apparels integrated with wearable sensors have achieved many smart functions, such as motion sensing, vital sign monitoring, and gesture recognition. Sensors for these applications require rapid response, high sensitivity, wide sensing range, and stable data acquisition capabilities. Textile fabrics have been widely used to fabricate flexible strain sensors owing to their high flexibility. However, the elasticity of ordinary textile fabrics is low, which limits their strain sensing range. E-textile consisting of natural fabrics has become a promising material to construct wearable sensors due to its comfortability and breathability on the human body. However, the fabric-based e-textile materials, such as conductive materials-treated textiles, generally suffer from the electrical and mechanical instability in long-term wearing. In particular, fabrics on the human body have to endure heat variation, moisture evaporation from metabolic activities, and even the immersion with body sweat. This chapter studied the knitted fabric material for wireless strain sensor application and its requirement.