Synthesis of a breathable and degradable silk fibroin/sodium alginate/aniline tetramer electronic skin by in situ polymerization method and for human motion monitoring

Electronic skin (e-skin) can monitor various physiological indicators of the human body in real-time, which has a wide application prospect in personalized medicine and health care. Nevertheless, the development of e-skin is hindered by the skin discomfort caused by the dense matrix of traditional e-skin and the electronic waste (e-waste) generated by non-degradable components. To solve these problems, this study proposes a piezoresistive e-skin with high breathability and significant degradability using a double-layer sponge as the substrate and aniline tetramer as the conductive medium. The aniline tetramer is adsorbed on the fibroin/sodium alginate matrix by in situ polymerization, which is simple, rapid, and less restrictive to prepare. The developed e-skin demonstrated a wide detection range (0–20 kPa), ultra-low detection limit (0.06 Pa), fast response time (20 ms), and good stability (1000 cycles). The e-skin also has good antibacterial ability, excellent water vapor transmission rate (7.65 kg m⁻²·day⁻¹), and biocompatibility, ensuring the comfort of long-term wearing. In addition, the e-skin is completely degraded into small particles after being immersed in sodium hydroxide solution for 48 h, greatly avoiding the generation of e-waste. In practical applications, e-skin responds quickly to weak stimuli and shows excellent sensing performance in human movement monitoring. This novel combination of the conductive oligomer and sponge substrate helps to promote the development of green electronics and implantable sensing devices.