OTS自组装分子膜的制备及其摩擦学测试

Synthesis and tribological properties of OTS self-assembled monolayers

采用分子自组装技术在银片表面成功制备了十八烷基三氯硅烷单层膜(OTS-SAMs)。运用接触角测试仪、极化曲线、循环伏安、SEM和紫外-可见分光光度计(UV-Vis)对OTS-SAMs薄膜的结构、形貌和性能进行了表征,并分析了载荷和滑动速度对薄膜摩擦学特性的影响。结果表明:紫外光照使基板由疏水变为亲水。极化曲线和循环伏安图显示在组装初期180s内,十八烷基三氯硅烷水解产物主要是与基体表面的羟基发生聚合反应,表现为"岛式"结构增长,随着组装时间的增加,有机硅烷分子之间发生聚合,当组装30min后,成膜过程趋于稳定,可以在基体表面形成平整、牢固和致密的自组装薄膜,这一结果同样由SEM得到验证。随着自组装膜的完善,其摩擦力降低,达到润滑的效果。另外,通过实验结果初步分析了OTS-SAMs的形成机理。

The octadecyhrichlorosilane（OTS） self-assembled monolayers on silver substrates were prepared by self- assembled technique. The effects of load, sliding velocity on tribological properties and the structure, morphology and per- formance of the OT^SAMs were investigated by contact angle test, polarization curves, cyclic voltammetry, SEM and UV Vis spectrometer. The results showed that the hydrophobic substrate was changed into hydrophilic by UV irradiation. Po larization curves, cyclic voltammetry showed that within 180S, the hydrolyzate of OTS mainly had the polyreaction with the hydroxy on substrate surface. OTS-SAMs have been formed on whole substrate with an ＂island＂ growth mode and 30minutes later, the formation of OTS-SAMs went stable with the layers smooth, secure and dense, and this result was ac- corded to SEM. With the improvement of SAMs,it reduced the silver substrates friction coefficient. The formation mecha- nism of OTS-SAMs was proposed according to the experiment results.