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采用分子动力学方法,模拟了在两块石英基板上由脂肪酸(C15H31COOH)组成的单层Langmuir-Blodgett(LB)膜间的摩擦特性,探究了超薄膜在滑动过程中的摩擦和结构机理.得出对于单层LB膜在滑动过程中,在速度小于60m/s时,随着速度的增大,其剪切压增大;在速度大于60m/s时,剪切压随速度的增加而减小.其链的倾斜角随着滑动速度的增加而减小.单层膜内的分子之间以氢键方式形成了较大的分子簇,由此导致了剪切压呈现较长的周期性,但在单层膜之间无氢键形成.
The molecular dynamics simulation is used to simulate the frictional properties of the monolayer Langmuir-Blodgett (LB) films composed of fatty acids (C15H31COOH) on two quartz substrates and to investigate the friction and structural mechanism of the ultrathin films during the sliding process. When the velocity is less than 60m / s, the shear pressure increases with the increase of velocity when the monolayer LB film slides. When the velocity is greater than 60m / s, the shear pressure decreases with the increase of velocity The chain’s tilt angle decreases with the increase of the sliding speed.Moreover, the molecules in the monolayer form large molecular clusters by hydrogen bonding, which leads to the long periodicity of shear pressure , But no hydrogen bond formation between the monolayers.