Skin-Inspired Permeable Structure-Gradient Fiber Mats for Pressure Sensing in Rehabilitation Assistance

Rehabilitation devices have launched to the market, allowing patients to perform rehabilitation exercises independently without the needs for constant presence of professionals. However, they are often developed based on thin-film plastics and enclosed in bulky encapsulation cases. Such design compromises the mechanical flexibility and permeability of the devices, leading to inconvenience and discomfort for users when wearing for exercise. We herein crafted a permeable, multilayered, structure-gradient fiber mat (SGFM) using a template-assisted layer-by-layer electrospinning technique to achieve triboelectric pressure sensing textiles with high sensitivity over a wide sensing range. By regulating the materials composition and microstructure, SGFM exhibit a gradual transition from rigidity to softness as it extends from its outermost layer towards the innermost layer, possessing a multiple gradient in terms of mat structures, dielectric property, and material modulus. As a result, triboelectric pressure sensing textiles constructed using SGFM show a substantial enhancement in pressure sensing performance compared to those constructed with homogeneous fiber mat without gradient structure. Importantly, the fibrous structure of SGFM endows the pressure sensors with air and moisture permeability, ensuring a comfortable wearing experience. We showcase the pressure sensing capability of these functional textiles in rehabilitation training scenario. By simultaneously monitoring the quadricep, pulse, and plantar pressures for posture tracking and correction, SGFM-based pressure sensing textiles demonstrate high application promise in rehabilitation assistance.