| As the rapid development of science and technology, many electronic component are gradually microminiaturizing, multifunction integrating, intelligentizing and having ligter weight. These development precipitate emerge of micro/nanoelectro mechanical systems(MEMs/NEMs). As the dimension of the systems decrease sharply, the interfacial clearance between the components are always a few of nanometers. Therefore tribological limitations such as stiction, friction and wear are the major problems that limited the efficiency, power output, steady-state motion, and reliability of MEMS/NMES devices. Therefore controlling the surface force as adhesion and friction acting in devices on the molecular level is of critical importance to successful operation of MEMS systems. Surface modification is regarded the effective approach to reducing the adhesion and friction in MEMS device. Attempt to deposit the organosilane films on the hydroxylated silicon substrate have been employed to reduce the adhesion between the contacting surfaces.MEMS components are routinely made from Si, which is a poor triblologycial material. The tribological properties of organosilane SAMs deposited on monocrystalline silicon were studed entensively. The results indicated that the organsilane SAMs possess excellent lubrication and adhesive-resistant ability. However, the SAMs could be worn easily. In order to improve anti-wear ability of SAMs, some kinds of inorganic nanoparticle with fine self-lubricating ability were bonded to surface modificated with function group by chemical force.Gold colloids were prepared via chemical reduction of HAuCl4 using sodium citrate as reductant. The Au nanoparicles were covalently bonded to silicon wafers surface modified with sulfhydryl group through Au-S bonds and form MPTS/Au composite film.The chemical composite of films were characterized by X-ray photoelectron spectroscopy (XPS); the contact angles of ultra-pure water on the MPTS films were determined with JC2000PC contact angle meter. Atomic force microscope (AFM) has been employed to study the morphology of the prepared films. The tribological properties of as-prepared films were tested on tribometer in a ball-on-plate contact configuration. It was investigated that the influence of surface topography and surface property on the tribological behavior.Some properties of films deposited on silicon wafers changed after Au nanoparticles convalently bonded to MPTS films, for example, contact angle increased and surface Gibbs free energy decreased. The change of surface properties improved the tribological behavior of films. The contact angle of MPTS/Au dual-layers film is greater than that of MPTS film; the surface roughness of the dual-layers is lower than the MPTS, so the friction coefficient is lower than that of the MPTS films. Furthermore, the feasibility of Au colloids chemisorbed on the thiol modified silicon wafer surface were analysed from angle of thermodynamics. According to the variation of contact angle with assembly time, we studied the practicability of the reaction between the Au and sulfhydryl group.In addition, the dual-components films with different chain length and functional group were prepared by self-assembling technology and the tribological properties of as-prepared films were evaluated on a friction and wear tester. It was found that the friction coefficients of MPTS and APTES film were higher than that of the OTS/MPTS and OTS/APTES dial-component films. Moreover, the results indicated that APTES and MPTS films have poor anti-wear ability, whereas the OTS/MPTS and OTS/APTES have fine anti-wear ability and stable friction coefficient.In this paper, there are 52 figures, 8 tables and 172 reference articles.
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