Engineering mussel-inspired adhesive towards stable conductive cotton fabric for strain and temperature sensing

Conductive cotton fabrics (CCFs) created by facile dip-coating exhibit great potential in smart materials but are limited by the poor stability and durability due to the weak adhesion between the cotton fabric (CF) substrate and the surface conductive coating. In this study, a mussel-inspired adhesive poly(vinyl alcohol)-g-3, 4-dihydroxybenzaldehyde (PVA-DBA) was synthesized to fabricate CCF for strain sensing and temperature sensing purposes. CCF was prepared by soaking CF in PVA-DBA aqueous solution, followed by dip-coating in cellulose nanofiber dispersed carbon nanotube (CNF&CNT) aqueous dispersion. The catechol structure of the PVA-DBA provided strong adhesion between CF and CNF&CNT, facilitating the coating of CNF&CNT onto the surface of CF firmly to generate stable and durable CCF. The CCF exhibited excellent strain sensing performance with gauge factors (GF) of 1.09 and 9.89 for strain ranges of 0–1.5% and 1.5–15%, respectively and response time of 80 ms. The CCF also demonstrated good temperature sensing behavior with a temperature coefficient of resistance (TCR) of −0.317%/°C. Furthermore, the CCF showed stability, repeatability, and durability against various mechanical destructions, such as ultrasonic treatment, tape peeling, and sandpaper abrasion.