High-water-content graphene oxide/polyvinyl alcohol hydrogel with excellent mechanical properties

In this study, high-water-content boron-cross-linked graphene oxide/polyvinyl alcohol (B-GO/PVA) hydrogels were prepared by a freeze/thaw method and immersion in boric acid solution for boron cross-linking. High-water-content B-GO/PVA hydrogels with a water/polymer mass ratio ranging from 19 : 1 to 49 : 1 (water content 95-98) could be obtained. It is found that a small addition of GO can lead to significant reinforcement of the tensile strength of B-GO/PVA hydrogels with an increase in elongation. Compared to B-PVA hydrogel, a 144% increase of fracture tensile strength is achieved when the content of GO is 0.1 wt% (similar to 0.609 MPa, water content similar to 95%). Meanwhile, compression and shear strength (0.1 MPa and 0.201 MPa, water content similar to 95%) of such hydrogels are increased by 26% and 35%, respectively. A method of acquiring high-water-content PVA hydrogels and the reinforcing mechanism of B-GO/PVA hydrogels are suggested. It is believed that such new high-water-content hydrogels are promising materials in the application of biomedical engineering and polymer electrolytes.