The Tribological Properties And Biocompatibility Of Graphene Oxide And Fluorinated Graphene Oxide Films Prepared By Electrophoretic Deposition

Micro-electro-mechanical systems (MEMS) is one of the most remarkablest of technologies in this century, it was quickly raised a series of research with the small size and functional integration. But, the adhesion、friction and wear become important factors in the reliable operation of MEMS, due to surface effect caused by the micron size of MEMS, even to the nano size. Because of limitations of MEMS production process, conventional liquid lubrication is not applicated. Self-assembled monolayers (SAMs), DLC solid lubricate films and other solid lubricate films were used to resolve the friction and wear. However, application of MEMS was limited by the poor wear resistances of SAMs and complex process of DLC films. In current, MEMS/NEMS applications become more widelyer in medicine, so that the toxicity and biocompatibility of materials become challenges of medical device. Graphene is considered to be the solid lubricant. But graphene films deposited by traditional vapor deposition method is not only high-cost, but also facing challenge that transition of the as-prepared films. To solve the above problems, a series of works were conducted in this thesis, and the main contents and results are as follows:1.Graphene oxide films were prepared on the silicon substrate by constant voltage electrophoretic deposition method. By control the time factor, a series of thin film was deposited. By characterized the graphene oxide films, and investigated the tribology properties, found that the deposition rate is gradually reduced, and at first the large-diameter graphene oxide was deposited, late the deposition of the small-diameter graphene oxide sheets, the mechanical properties of the film were gradually increased. Through tribology test of graphene oxide film, found that fewer oxygen-containing group and defects graphene oxide is more conducive to reducing friction wear.2.By control current factors, a series of graphene oxide films were prepared by constant current chapter electrophoretic deposition, and the graphene oxide films were characterized, while they investigated tribological properties. the constant voltage deposited graphene oxide films were compared, found constant current deposition of graphene oxide film regardless of the amount of wear in the friction coefficient is relatively constant voltage are significantly improved.3.Fluorinated graphene oxide (FGO) was prepared by hydrothermal method, the F/C can reach 29%, and FGO can be well dispersed in the water. Thus FGO films were deposition on silicon substrates by the constant current electrophoretic deposition mothed. the thickness of FGO films can be adjusted by operate deposition current. by research the law that the deposition current was the impact of the roughness and adhesion of FGO films, found that FGO film has the best tribological properties under 2mA: the friction coefficient is reduced to 1/4 of the silicon wafer, wear volume is also reduced of 1/94. In short, FGO films prepared by electrophoretic deposition method can effectively reduce the friction coefficient, extend the wear life. In terms of biocompatibility, FGO has good biocompatibility and can promote the growth of MC3T3-E1 cells. It is demonstrated the FGO films have enormous potential in medical MEMS/NEMS.