Electro-conductive and temperature-sensitive poly(N-isopropylacrylamide) composite hydrogels with improved mechanical properties

Poly( N -isopropylacrylamide) (PNIPAAm) hydrogel with temperature-sensitive properties can be potentially applied in smart response area. However, poor mechanical and non-conductive characteristic have greatly restricted its widespread application. In this work, PNIPAAm composite hydrogels containing graphene aerogel (GA) and graphene oxide (GO) were prepared via vacuum-assisted backfilling and in-situ polymerization. After an introduction of 0.29 wt% GA and 0.09 wt% GO, the compressive strength and modulus of PNIPAAm hydrogel increase by 100% and 582%, respectively. Moreover, the ternary composite hydrogel has a good electric conductivity, reaching up to 0.52 S/m, due to the electro-conductive network of GA. Combining the good conductivity and itself temperature-sensitive property of PNIPAAm, a smart switch was assembled and could switch off automatically under a high voltage, which has potential applications in sensor area.