Mechano-adaptive thin film of graphene-based polymeric nanocomposite for enhancement of lubrication properties

Abstract

Intriguing low frictional properties of 2D materials can be harnessed for thin-film lubrication in small-scale devices by making their mechano-adaptive coatings. Herein, the reduced graphene oxide-polystyrene (rGO-PS) nanocomposite synthesized by single-step chemical processing of graphene oxide and polystyrene is applied to prepare self-lubricating thin film over the silicon substrate. The non-covalent π-π interaction between the aromatic rings of polystyrene and the π-electron network of rGO furnished excellent interfacial adhesion and extended the mechanical strengthening and lubrication properties. The interfacial interaction is further supported by higher glass transition and thermal decomposition temperatures of the rGO-PS nanocomposite. The rGO-PS thin film with a uniform thickness of 850 nm is coated on a silicon surface by a spray pyrolysis deposition technique. The rGO-PS thin film showed significantly low friction (μ = 0.12) compared to the silicon substrate (μ = 0.6). The microscopic and spectroscopic analyses confirmed the deposition of a graphene-based thin film on the counter interface of the steel ball. Furthermore, the rGO-PS thin film couldn’t damage/rupture even after 100,000 cyclic contacts, which revealed its remarkable wear-resistivity. The excellent mechano-adaptability and low frictional properties of rGO-PS thin film promise the potential of 2D nanomaterials for thin-film lubrication applications.