The objective of this research is to study the interfacial mechanical responses of advanced composites composed of chemically modified carbon fibers in thermoplastic matrix. Electron spectroscopy will be used to identify the surface composition of various surface treated carbon fibers. Scanning electron microscopy will be used to probe the modes of mechanical failure of the resultant composites. Experiments will be conducted in an environmental chamber and the interfacial failure during tensile testing will be observed in-situ with a video camera. The results are expected to facilitate the design of superior polymeric composites.