Electrical and thermal conductivity and tensile strength of degummed silk fibers coated with carbon nanotubes using a polydopamine-assisted dip-and-dry method

• SWCNT/silk composites were prepared from silk at different degumming ratios. • Degumming ratio affected properties of the composite fibers. • Degumming enhanced SWCNT adhesion, improving electrical & thermal conductivities. • Further degumming led to fibroin loss, reducing tensile strength and elongation. Electronic textiles are emerging as key materials for next-generation flexible wearable devices. Silk is an attractive candidate owing to its high durability, light weight, and flexibility, while single-walled carbon nanotubes (SWCNTs) provide excellent electrical and thermal conductivity along with chemical stability. However, achieving high conductivity in CNT/silk composite fibers without compromising the intrinsic strength of silk remains a significant challenge. In this study, we fabricated SWCNT/silk composite fibers using a polydopamine (PDA)-assisted dip-and-dry method and systematically optimized the silk degumming ratio to obtain fibers with excellent electrical and thermal conductivity. At an optimal silk degumming ratio of 25 wt%, the PDA-coated SWCNT/silk composite fibers exhibited an excellent electrical conductivity of 315 S/cm, a high tensile strength of 150 MPa, and a thermal conductivity of 6.3 W/mK. By simultaneously achieving high electrical, mechanical, and thermal performance, the proposed strategy overcomes key limitations of existing CNT/silk composites and highlights the potential of these fibers as promising materials for next-generation flexible electronic textiles.