Impact of graphene oxide on dye absorption in composite hydrogels

Graphene oxide (GO) based composite hydrogels were prepared by incorporating GO or polydopamine coated GO (PGO) into poly(methacrylic acid) (PMAA) hydrogel systems. The direct dispersion of GO within the hydrogel network was found to be inconsistent, probably due to the hydrophilic properties of GO. By coating GO with polydopamine, the dispersion within the hydrogel network was found to be greatly improved. The incorporation of GO or PGO had different effects on the degree of swelling (D-S) of the hydrogel system. The Ds of the composite was significantly increased after the addition of GO and PGO filler with the GO samples showing considerable variation in swelling compared to PGO. Compared to the blank gel, the incorporation of GO or PGO were found to greatly improve the absorption of both methylene blue and methyl red dyes with different charges.