Preparation and tribology studies of alkyl carboxylic acid monolayer films on PEI-coated glass substrate

Monolayer film of n-Alkanoic acid expected to be an excellent lubricant for micromachines was successfully prepared on PEI-coated glass substrate. The results of Contact-angle measurement and X-ray photoelectron spectroscopy (XPS) show that n-Alkanoic acid chemically attaches to the functional surface of PEI coatings. As a result, steady monolayer film of n-Alkanoic acid is prepared in the presence of a covalent amide bond between carboxylic group in n-Alkanoic acid and the primary or secondary amine groups in PEI. The lower surface energy generates lower friction forces and well-ordered and high packing densities of organic films correspond to excellent properties of tribology.