Highly Stretchable, Sensitive, and Robust Wearable Strain Sensor Based on CNTs/AgNWs Nanocomposite for Health and Fitness Monitoring

This letter reports a resistive-type wearable strain sensor fabricated using an electrically conductive hybrid network of single-walled carbon nanotubes (CNTs) and silver nanowires (AgNWs). AgNWs degrade over time due to silver corrosion in ambient conditions, leading to electrode failure. To mitigate this issue, CNTs were incorporated as a protective shield, effectively interlinking the AgNWs. This not only improved the stability and durability of the AgNWs but also resulted in a robust and highly conductive CNTs/AgNWs hybrid network. The hierarchical CNTs/AgNWs-based strain sensor exhibited better performance, achieving a large elongation of up to 100% with high sensitivity, demonstrated by a gauge factor (GF) of 79. It also featured fast response time of 42 ms and outstanding mechanical stability, maintaining performance over 5,000 stretch-release cycles. The sensor's performance was assessed under normal environmental conditions for a period of 180 days (approximately six months), showing minimal degradation in GF. This provides valuable insights into long-term changes, aiding the development of more robust, durable, and reliable nanocomposite-based strain sensors for practical applications. The sensor was used to monitor various human motions, including finger, throat, and elbow movements.