Effectively exerting the reinforcement of polyvinyl alcohol nanocomposite hydrogel via poly(dopamine) functionalized graphene oxide

Nature-inspired coating with polydopamine (PDA) is a promising way to improve the performance of graphene oxide (GO) based nanocomposites due to its high ability to enhance interactions in matrix-disperse systems. Here, we examined the capability of two types of PDA to develop the reinforced polyvinyl alcohol (PVA)/GO hydrogels. In the first mode, dopamine hydrochloride was polymerized as nanoparticles and then incorporated into PVA solution with GO nanoplatelets (P-NG hydrogel). In the second mode, polydopamine was polymerized in the presence of GO nanoparticles to obtain PDA surface-modified GO and then PVA nanocomposite hydrogel (P-CG sample). Rheological and tensile findings revealed that both types of PDA could act as a coupling agent and dramatically ameliorate viscoelastic and mechanical properties through establishment of hydrogen bonds and π-π interactions with the composite components. Also, PDA made the PVA-GO interfacial adhesion robust, leading to excellent self-healing properties. The outputs indicated that PDA in direct coated state could present better efficiency compared to the PDA nanoparticles. Moreover, porous network structure size in P-CG was smaller compared to that in P-NG, due to the increased crosslink density and higher net points interaction between the GO platelets and PVA chains, which leads to strong interfacial adhesion.