Influences of graphene oxide/sulphonated polyethersulphone nanoplatelets on the wettability, nanomechanical and tribological performances of polyethersulphone composites under various relative humidity conditions

ABSTRACT Graphene oxide (GO) nanoplatelets were functionalised using sulphonated polyethersulphone (PES-SO3H) and subsequently as nanofiller incorporated into the PES matrix to improve its comprehensive performances. Influences of GO/PES-SO3H nanoplatelets on the surface wettability, nanomechanical property and tribological behaviours of GO/PES-SO3H/PES composite under various relative humidity were investigated. Test results indicate that the introduction of GO/PES-SO3H dramatically decreases the water contact angles and increases the nanoindentation hardness of PES. The effects of relative humidity on the friction coefficients of GO/PES-SO3H/PES composites are far less than that on the wear rates of PES composites. Compared with the pristine PES, the PES-matrix composite containing 1.0 wt-% GO/PES-SO3H nanoplatelets exhibits the minimum friction coefficient (0.11) and wear rate (5.83×10−14 m3/N m) under the high relative humidity of 90%. This is attributable to the reinforcement effect and hydrogen bonding interaction of GO/PES-SO3H nanoplatelets as well as the uniform and ultrathin PES self-lubricating transfer films.