Silk Nanofibers/Carbon Nanotube Conductive Aerogel.

Natural silk nanofibers (SNF) are attractive conductive substrates due to their high aspect ratio, outstanding mechanical strength, excellent biocompatibility, and controllable degradability. However, the inherently non-conductivity severely restricts the potential sensor application of SNF-based aerogels. In this work, the conductive nanofibrous aerogels with low-density achieved through freeze-drying by dispersing carbon nanotubes (CNT) into SNF suspension. The addition of CNT significantly increases the conductivity with improved mechanical properties of composite aerogels. SEM results reveal that the distinct hierarchical structure comprising micropores and nanofibrous networks within the pores is formed when CNT content reached 30%. Furthermore, increased cell viability suggested the excellent biocompatibility of SNF-CNT-based conductive aerogel for tissue-engineering applications. Subsequently, the elastic water-borne polyurethane (WPU) is incorporated to SNF-CNT system to construct aerogel with good sensing properties. The introduction of WPU demonstrates enhanced compressive performances and an exceptionally high elastic recovery ratio of 99.8%, thereby exhibiting a stable and lossless strain-sensing signal output at 5% strain. This study provides a feasible choice and strategy for exploring the potential application of SNF in functional aerogels.