Dopamine-dependent graphene oxide modification and its effects on interfacial adhesion of carbon fiber composites

Abstract

Different concentrations of dopamine were utilized to be auto-oxidized onto graphene oxide (GO) for tuning the size of formed polydopamine (PDA) nanospheres in order to settle the issues regarding the weak bonding of GO with carbon fiber, cumbersome manipulation and environmental pollution. After grafting PDA, the adherence amount of GO on fiber significantly improved, but descended with the increase of PDA size. When 0.05 g dopamine was applied, the PDA functionalized GO treated fiber showed 64.1 and 46.1% gain in interfacial shear strength over those of untreated fiber and pure GO modified fiber. The results indicated that the strengthening reasons belonged to more reactive amino or imino groups, obviously improved wettability and rougher fiber surface that contributed by suitable sized PDA nanospheres. Furthermore, the surface characteristic of GO and fiber are highly dopamine concentration dependent.