Preparation And Tribological Properties Of Self-assembled Monolayers On Copper And Zinc Substrates

Self-assembled monolayers (SAMs) is a new kind of super thin film that it was developed in 1980s. SAMs can be widely used in chemical, optical, biological, mechanical and electrical fields for its better orderliness and orientation. Because of their stable structure and tight packing density, SAMs can prevent corrosion, reduce friction and wear. In this thesis, the homogeneous and dense silane and fatty acid nano thin films were prepared on the copper and zinc substrates by molecular self-assembly technology, and their conformation, wettability and tribological properties were studied, in order to obtain the thin films which can improve the tribological properties of the copper and zinc substrates. The main results are showed as follows:(1) The friction coefficient of Zinc substrate can be reduced obviously by the organic films of stearic acid constructed on Zinc, and the substrate can be protected obviously by the stearic acid films. The Zinc surface were dipped into DMF solution, then the stearic acid films were built on the above surface, the contact Angle of water of the compound films reached 155°. The friction of the substrate was reduced and excellent wear-resisting characteristics were presented on the compound films.(2) The stearic acid, oleic acid and lauric acid films are prepared on the substrates of copper by molecular self-assembly technology. Compared with the three films, the tribological properties of the stearic acid films are the best.(3) With using the molecular self-assembly technology, (Heptadecafluoro-1,1,2,2- tetradecyl) trimethoxysilane (FAS) monolayer was deposited on the surface of the copper and the copper that dipped in NaOH solution, they obviously have hydrophobic property. The wear life of the FAS films on the copper is 390s at the lower load of 0.2N and it can protect the copper substrate, yet the eroded copper and FAS SAMs on the eroded copper substrates can,t play the role on reducing the friction coefficient.The copper and zinc metal are widely used in industry and micro mechanery, yet that they are corroded easily and own high friction coefficient can result in serious economic damagement. In this article, the silane, stearic acid, oleic acid and lauric acid nano thin films were prepared on the copper and zinc substrates by molecular self-assembly technology, and the friction coefficient of the thin films were researched systematically. The results here can play great role in real application of copper and zinc.