Preparation and properties of graphene oxide-regenerated cellulose/polyvinyl alcohol hydrogel with pH-sensitive behavior

In this study, graphene oxide reinforced regenerated cellulose/polyvinyl alcohol (GO–RCE/PVA) ternary hydrogels were successfully prepared via a repeated freezing and thawing method in NaOH/urea aqueous solution. The effect of GO content on the mechanical properties, swelling behavior, water content of composite hydrogels was investigated. It was found that the mechanical properties of GO–RCE/PVA ternary hydrogels were largely enhanced relative to RCE/PVA hydrogels. With the addition of 1.0 wt% GO, the tensile strength was increased by 40.4% from 0.52 MPa to 0.73 MPa, accompanied by the increase of the elongation at break (from 103% to 238%). Meanwhile, GO–RCE/PVA ternary hydrogels performed the excellent pH-sensitivity, and the higher pH leaded to higher swelling ratio. With 0.8 wt% GO loading, the swelling ratio of GO–RCE/PVA ternary hydrogel was improved from 150% (pH = 2) to 310% (pH = 14). In addition, a slight increase in the water content of the ternary hydrogel was achieved with increasing concentrations of GO. It is believed that this novel ternary hydrogels is a promising material in the application of biomedical engineering and intelligent devices.