Application of poly (dimethyl diallyl ammonium chloride)−reinforced multifunctional poly (vinyl alcohol)/ polyaniline hydrogels as flexible sensor materials

The design of multifunctional hydrogel sensor materials with comprehensive properties such as frost resistance, good reusability, adhesion, and flexibility needs to be developed to meet the demands of complex environments. Herein, a conductive, semi-interpenetrating network hydrogel was constructed from poly (vinyl alcohol), polyaniline (PANI), and poly (dimethyl diallyl ammonium chloride) (PDDA), and the process assisted by the Hofmeister effect. A double conductive pathway hydrogel with types of PDDA and PANI polymers was formed simultaneously to provide excellent conductivity (1.217 S/m−1) for the hydrogel. With the increase in the concentration of PDDA from 0 to 16 wt%, the mechanical strength increased from 0.066 MPa to 0.34 MPa, and the modulus of elasticity and toughness increased by 684.9% and 748.8%, respectively. The hydrogel can be efficiently generated as a strain sensor material with excellent sensitivities of GF= 2.337 and S= 3.229%/KPa under tension and compression, respectively. The hydrogel could be used as an electronic skin and be used for the monitoring of even small strains in the skin caused by pulse beats. In addition, the hydrogel has excellent temperature sensitivity (1.575%/℃), frost resistance (−53.45 ℃), self-healing capability, and reusability. Data will be made available on request.