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)single bondO2single bondN2 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 TMSsingle bondO2single bondN2 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 TMSsingle bondO2single bondN2 plasma-polymerized SiOxCyNz.