Structural and tribological characteristics of poly(vinylidene fluoride)/functionalized graphene oxide nanocomposite thin films

The possibility of engineering the crystalline structure and tribological properties of poly(vinylidene fluoride) (PVDF) thin films (300 nm) using functionalized graphene oxide (FGO) was evaluated. Samples with 0.0, 0.5, 1.0, and 2.0 wt% FGO in the feed were spin cast on Si-wafer, characterized by X-ray photoelectron (XPS), Fourier-transform infrared and Raman spectroscopies, atomic force and scanning electron microscopies, and tribological analyses. XPS and Raman studies were confirmed the incorporation of FGO into the PVDF matrix. PVDF predominantly contained the α-phase. FGO suppressed the growth of the α-phase and favored the formation of the ferroelectric β- and γ-phases. The surface topography changed from featureless to spherulites with or without well-grown dendrites upon FGO incorporation. In case of tribological characteristics, when a 10 mN normal load was applied in a reciprocating motion, the bare Si-wafer, PVDF, and PVDF-FGO-2.0 showed substantial damage after 50, 125, and 50 cycles, respectively. PVDF-FGO-0.5 was very stable even after 120 cycles whereas PVDF-FGO-1.0 showed mild abrasion.