Molecular Assembly of Ultrathin Polymer Films: An Application In Tribology

We demonstrate the application of covalent molecular assembly in fabricating robust thin film structures. An anhydride functionalized polymer has been deposited over an amine-terminated silicon surface through covalent binding. The process conditions to achieve reproducible molecular thicknesses for the polymer film have been optimized. X-ray photoelectron spectroscopy, atomic force microscopy and ellipsometry were employed to study the interfacial chemistry, morphology and thickness of the assembled film. The films show excellent stability and mechanical strength attributable to the covalent interlayer linkage. The applicability of such polymeric film as an intermediate layer between Si and PFPE to improve the tribological properties of PFPE films has been demonstrated. Such films showed wear life of >100,000 cycles and can potentially be used as lubricants in several technological applications, such as information storage devices and micro-electro-mechanical systems (MEMS).