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

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, selfrecovery 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 degrees C, responsive time 3.3 s and -1.062 %/oC in 37-75 degrees 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.