Fabrication and Characterization of Single‐Layer Textile‐Based Flexible Pressure Sensors for Smart Wearable Electronics Applications

Abstract

Some key requirements for a sensor to qualify as a wearable sensor include biocompatibility, aesthetics, comfort, reliable sensing, and signal reliability. The last three are essential factors for acquiring continuous and stable data from a human body. [5] Textile-based sensors are often developed through techniques [6,7] with certain limitations in creating free-form sensor designs because of their complex manufacturing processes. Machine stitching has recently been studied as a potentially scalable method to fabricate textile-based sensors. [8] Different stitch classes have been investigated to study the impact of loop-based stitch structures on the performance of sensors. [9] Also, the effect of stitching parameters on the sensing performance of piezoresistive sensors has been studied. [10] Developing a high-performance textile-based pressure sensor requires an electrically conductive textile medium (fibers, yarn, or fabric) with durability against external forces. [11] Conventional textiles are nonconductive materials and require some practical

Moisture‐Insensitive Force Sensor Yarns and Fabrics to Monitor Biological Motion

“…The sensitivity of a force sensor could be compared with that of flexible pressure sensors, for which a detection range of ≈0-50 kPa has been reported thus far. [25][26][27][28][29][30][31][32][33][34] However, the proposed sensor yarn was entirely composed of fibers and exhibited excellent texture as a sewing yarn that could be sewn into woven or knitted fabrics, as explained in Section 2.3. The sensor characteristics in Figure 2b exhibit a nonlinear trend in which the rate of increase in the sensor output change rate decreased as the external force increased, which we believe is similar to the percolation theory model when the electrical conductivity in a compound system in which a conductive material, such as CNT is dispersed in an insulating material is considered.…”

“…Similar to this basic principle, piezoresistive sensor fibers, in which conductive materials are dispersed in insulating materials, have been extensively investigated. [9,[25][26][27][28][29][30][31][32][33][34] The conductive materials include carbon nanotubes (CNTs), [9,25] CNT-embedded polyurethane, [26] graphene oxide, [27,28] graphene nanoplateletcoated threads, [29] piezoresistive rubber, [30] mixed fibers of carbon-black-coated filaments and insulating filaments, [31,32] graphite-based textile semiconductor, [33] and insulating fibers with slight conductive impurities. [34] Air gaps and elastic materials, such as polyurethane and silicone, have been reported as insulators for dispersing these materials.…”

“…Third, the method employed to implement the sensor function in fabrics. Previous studies on piezoresistive sensor fibers [24][25][26][27][28][29][30][31][32][33] realized the resistance change in the form of a fiber. The requirement of separate preparation of two electrodes in the measurement system poses practical challenges, although suitable for precise studies on yarn properties.…”

“…[34] Air gaps and elastic materials, such as polyurethane and silicone, have been reported as insulators for dispersing these materials. [25][26][27][28][29][30][31][32][33][34] For example, sensor threads in which conductive fibers are wrapped around a urethane fiber have been proposed. When the thread is strained, the electrical contact between the conductive fibers changes, changing the resistance, which is used for detecting the applied tensile force.…”

A Novel Elastic Conductive Yarn for Smart Textile Applications

“…[1][2][3] This development facilitates the conformability of clothing, such as aesthetics and comfort, along with electronics compliance, such as biocompatibility and signal reliability. [4,5] There is ongoing research focused on scalable fabrication techniques and aimed at developing textile-based wearable electronic components and sensors. [6][7][8][9][10] Conductive yarns and conductive fabrics are the key elements of e-textiles.…”