A flexible, highly sensitive, and anti-strain interference sensing fabric based on conjugated electrospinning core-shell conductive nanofiber yarns for ultra-stable pressure sensing and human-machine interaction

Fabric-based pressure sensors featuring flexibility, comfortability and integration have been widely used for detecting physiological health signals of human body and in the smart wearable electronics. However, they are prone to interference from strain stimuli while sensing pressure, making it a challenge to accurately discriminate between pressure and strain. To overcome this challenge, our research provides a breakthrough insight in fabricating capacitive pressure sensing fabric that is the design of yarn's internal structure and fabric's organizational structure. In this work, a sensing fabric with a unique rib 2 x 2 structure is weaved by conjugated nanofiber yarns with a core-shell structure. The pivotal role of the core-shell structure lies in the improvement of pressure sensitivity and unique rib interlocked structure leaves the stretching room for the unchanged conductive path. Their synergistic effect makes the sensor highly sensitive to pressure but insensitive to strain even up to 100 % stretching. Notably, This NYPS-R-2x2 is endowed with a high sensitivity of 101.03 kPa(-1), while exhibits ultra-low detection limit of 0.14 Pa, fast response/recovery time of about 36/54 ms, outstanding resolution and excellent stability under 10,000 compression cycle tests. Moreover, strain interference factor < 8 % shows that electrical change caused by strain is very tiny compared with pressure, realizing anti-strain interference ability. The mechanism of pressure sensing and anti-strain interference are determined through model analysis and experimental verification. Additionally, precise monitoring of human physiological movements and human-computer interactions such as intelligent keyboards can be achieved by NYPS-R-2x2. This work provides new insights into the pressure sensing with anti-strain interference and preparation and application of intelligent fabrics in the wearable electronics and human-machine interaction.