Tunicate cellulose nanocrystal reinforced conductive multi-responsive hydrogel with super flexible, fatigue resistant and self-healable capability for antibacterial flexible sensors

Abstract

Despite the current progress in multistimuli-responsive ionic conductive hydrogels, it is still a significant challenge to develop superior multistimuli-responsive ionic conductive hydrogels with satisfactory mechanical property, antibacterial and self-healing capability to meet the practical applications. In this study, a novel inherently antibacterial ionic conductive hydrogel (PCNAT-Fe) with excellent flexible, fatigue resistant, self-recovery ability, temperature/pH-responsive ability and tensile strain/temperature/pH-sensitive conductivity was fabricated via one step copolymerization of acrylic acid (AA) and N-isopropylacrylamide (NIPAM) in the presence with carboxymethyl chitosan (CMCS), Tunicate cellulose nanocrystals (TCNCs) and FeCl3. Benefiting from the synergy of TCNCs, FeCl3 and thermos/pH-sensitive materials, the hydrogel is concurrently endowed with excellent stretchability (1237.2 %), high conductivity (6.62S/m), biocompatibility, anti-drying capability, excellent mechanical and conductive repeatability. More importantly, the PCNAT-Fe hydrogel can ingeniously perceive large/subtle deformation (GF: 0.75 in the strain range of 0–50 %, 1.02 in the strain range of 50–150 %, response time 0.96 s and 2.81 in the strain range of 150–350 %, 3.40 in the strain range of 350–700 %), external temperature (TCR: −1.452 %/oC in 25–37 °C, responsive time 3.3 s and −1.062 %/oC in 37–75 °C) and pH values via the changes of relative resistance within fast responsive time, which can be applied as human–computer interfaces to interactively monitor human motions, ambient temperature and pH values in real time.