Reinforcement effect of multilayer graphene in PVA hydrogel during large strain tension

Hydrogels have been widely studied as promising materials in several applications, such as wearable devices, electronic skin, soft robot, artificial muscle and articular cartilage, due to their numerous prominent performances. However, the inferior mechanical property, especially difficult for hydrogels to simultaneously obtain high tensile strength and elongation, limits their further clinical application. Thus, here we used the multilayer and single layer graphene (MG and SG) as reinforcement fillers to improve the mechanical performances of neat polyvinyl alcohol (PVA) hydrogels. Our results showed that the high tensile strength and fracture elongation were simultaneously obtained from PVA/0.20wt%MG hydrogel, which were higher than those of PVA/SG hydrogel. Further, the elastic modulus of PVA/graphene composites was measured by calculating the effective modulus of SG and MG within PVA matrix from the Raman shift of D peak for the PVA/SG and PVA/MG composite hydrogel, respectively. The findings demonstrate the possibility of in situ exfoliation of MG in hydrogels under large tensile strain.