A novel bio-inspired multi-functional collagen aggregate based flexible sensor with multi-layer and internal 3D network structure

A novel multi-functional sensor was fabricated with mull-layer and internal 3D network structure via two-step assembly that mimicked the natural hierarchical skin model. The collagen aggregates (CA) derived from chromium-containing waste leather were used as the substrate while polyaniline (PANi)-acidified mull-walled carbon nanotube (H-MWNTs) composites were employed as the conductive materials (P-M). The multi-functional flexible sensor was assembled resulting in mull-dimensional recognition ability (including compressing (gauge factor (GF) = 5.2), bending (GF = 9.2), and twisting strains), fast response (110 ms), and broad dynamic response range (28 Pa-100 KPa). Notably, the multi-functional sensor had superior sensing performance to humidity and comfortable wearing performance. Owing to these merits, the fabricated sensor with multi-functionality and intelligence can potentially act as the artificial skin for robot hand to detect weak pressure and humidity changes, displaying great promise for applications in the fields of real-time health monitoring, biomedical, and intelligent robots.