Flexible porous non-woven silk fabric based conductive composite for efficient multimodal sensing

Silk-based conductive composites have attracted much attention for applications in flexible smart electronics. However, silk-based conductive composites that combine high air permeability, Joule heat management, electromagnetic interference (EMI) shielding and multimodal responsiveness are still challenging. In this paper, flexible porous non-woven silk fabric (nSF)-based conductive composites with the aforementioned properties are designed and developed by a freeze-induced assembly and surface micro-dissolution adhesion (FASMA) process to introduce carbonyl carbon nanotubes (C-CNTs), MXene and thermoplastic polyurethanes (TPU) into the inter-fiber network structure of nSF, with the aim of constructing a high-performance multimodal sensing platform. Functioning as a flexible strain sensor, the nSF-based composite can detect strains as low as 0.05 % with rapid response and recovery time of 125 ms and 146 ms, respectively, and can be used to detect full-size human motion signals. The nSF-based composite has a good humidity response at 0–85 % relative humidity (RH) and a sensitive and reliable thermal response. In additionally, the nSF-based composites also have Joule heat management and EMI shielding functions. All these multi-functional applications demonstrate the advantages of the prepared flexible porous nSF-based composites in the field of flexible smart electronics.