Preparation And Tribological Behaviors Of Polymer Nanocomposite Film

Technology of lubrication and wear-resistance, which may realize the film ultra-low friction and zero wear, is pivotal to develop micromachine and microelectromechanical systems (MEMS). Under the drive of the underground, many research groups have actively explored and synthesized the systems of film forming, which themselves possess the property of low friction and wear-resistance, and lucubrated the mechanism of film forming and different influencing factor, so that they may better open up the application of molecular ordered ultra-thin nanofilms in the area of tribology.We successfully prepared various polymer-based nanocomposite films. Cu(OH)₂ nanoparticle-containing PAA/PDDA multilayer films have been prepared by combination of the layer-by-layer self-assembly technique with in situ chemical reaction. Cu nanoparticle-containing PDDA/PSS multilayer films and SiO₂ nanocomposite films have been prepared by spin-assisted layer-by-layer self-assembly technique. The films were characterized by means of ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The friction and wear behaviors of the films sliding against 440C stainless steel counterparts were evaluated using a UMT-2 multifunctional micro tribometer. The morphologies of wear scars formed on the counterface and wear tracks obtained on the film during tribological test were examined using a scanning electron microscopy. The experimental results show that Cu(OH)₂ nanoparticle-containing PAA/PDDA and Cu nanoparticle-containing PDDA /PSS multilayer films displayed excellent tribological behaviors, which were attributed to nanoparticles formed in films enhancing the load-carrying capacity. For SiO2 nanocomposite film, the tribological performance was improved greatly, which was influenced by two factors. Besides the factor mentioned above, the other is that -NH₃⁺ in the surface of SiO₂ in the acidic water bound to the–COO^- of PAA. Subsequently be heated, the static force was converted to covalent bond, which enhanced the bonding strength of films.