Enhanced scratch resistance of flexible carbon fiber-reinforced polymer composites by low temperature plasma-polymerized organosilicon oxynitride: The effects of nitrogen addition

An investigation is conducted on enhanced scratch resistance of flexible carbon fiber-reinforced polymer composites (FCFRPCs) by low temperature plasma-polymerized organo-silicon oxynitride (SiOxCyNz) at varying N2 concentrations. It is found that the organic–inorganic hybrid films (SiOxCyNz) deposited on FCFRPCs using tetramethylsilane (TMS)O2N2 plasmas at low temperature dramatically improve the scratch resistance of FCFRPCs. Scratch resistance is greatly enhanced from an overwhelming presence of scratching (100%) on untreated FCFRPCs to a complete lack of scratching (0%) on TMSO2N2 plasma-polymerized FCFRPCs with steel wool for 250 cycles at 200 g loading. The scratch resistance of FCFRPCs is found to be highly dependent on their surface characteristics including hardness, surface morphology, surface compositions and chemical bonds of TMSO2N2 plasma-polymerized SiOxCyNz.

► SiOxCyNz synthesized onto flexible carbon fiber-reinforced polymer composites (FCFRPCs) by plasma polymerization.
► Flexible and hard SiOxCyNz films synthesized using tetramethylsilane (TMS)O2N2 plasmas.
► High proportions of Si(O)4 and SiNO bonds provide a high surface hardness of 7H.
► Higher deposition rate offers lower proportion of grain boundary.
► Lower proportion of grain boundary results in smoother surface.