Self-assembly investigation of aromatic thiols at interface of carbon fiber/epoxy composites

A new method based on the molecular self-assembly was proposed for the carbon fiber surface modification. The carbon fiber surface was first metallized by electroless Ag plating and then covered by organic compound self-assembly films. The surface-enhanced Raman scattering spectroscopy (SERS) analysis verified that two aromatic thiols with different end-groups chemisorbed onto the Ag-plated carbon fibers and formed a lie-down phase and tilt-angle phase corresponding to the substrate surface. XPS further proved the chemisorption of self-assembly films on carbon fiber surface via the formation of S-Ag bond. The interfacial bonding strengths of modified carbon fiber/epoxy composites were improved. The relationship between the structures of interfacial regions and properties of the micro-composites was revealed.