Multi-walled carbon nanotubes functionalized silk fabrics for mechanical sensors and heating materials

Abstract MWCNTs@silk fabric (CSF) with single-side, good conductive property was prepared via a surface micro-dissolution strategy. In this method, the partial dissolution of silk fibers was regulated by the concentration formic acid and the interaction between the protein and its solvent. The dissolved silk protein served as the physical crosslinking agent that connected dispersed carbon nanoparticles to form a continuous conductive network, avoiding complex chemical treatments and the use of physical adhesives. CSF possessed good electrical conductivity (468 Ω cm−1) and durability. Moreover, CSF had a unique single-side loading characteristic and its resistance changed from 98.4% to 102% of the initial value with the bending angle varying from −112.5° to 112.5°, so CSF could be used as sensors to monitor the mechanical activities effectively. Patterned conductive MWCNTs@silk fabric (PCSF) was fabricated by using patterned templates during the deposition process and used for wider applications, such as flexible switches (F-shaped PCSF), soft keyboards (keyboard-like PCSF), electric heating materials (S-shaped PCSF) and microwave-assisted heating materials (butterfly-like PCSF).