1 research outputs found
Nanofriction of Graphene/Ionic Liquid-Infused Block Copolymer Homoporous Membranes
We have infused graphene/ionic
liquid into block copolymer homoporous
membranes (HOMEs), which have highly ordered uniform cylindrical nanopores,
to form compact, dense, and continuous graphene/ionic liquid (Gr/IL)
lubricating layers at interfaces, enabling a reduction in the friction
coefficient. Raman and XPS analyses, confirmed the parallel alignment
of the cation of ILs on graphene by the π–π stacking
interaction of the imidazolium ring with the graphene layer. This
alignment loosens the lattice spacing of Gr in Gr/ILs, leading to
a larger lattice spacing of 0.36 nm in Gr of Gr/ILs hybrids than the
pristine Gr (0.33 nm). The loose graphene layers, which are caused
by the coexistence of graphene and ILs, would make the sliding easier,
and favor the lubrication. An increase in the friction coefficient
was observed on ILs-infused block copolymer HOMEs, as compared to
Gr/ILs-infused ones, due to the absence of Gr and the unstably formed
ILs film. Gr/ILs-infused block copolymer HOMEs also exhibit much smaller
residual indentation depth and peak indentation depth in comparison
with ILs-infused ones. This indicates that the existence of stably
supported Gr/ILs hybrid liquid films aids the reduction of the friction
coefficient by preventing the thinning of the lubricant layer and
exposure of the underlying block copolymer HOMEs