双电层对纳米流体润滑与摩擦影响的MD模拟

Molecular Dynamics Simulation of the Influence on Nanoscale Fluid Lubrication and Friction of Electric Double Layer

采用分子动力学方法对带电和不带电两硅板之间的水分子润滑薄膜进行模拟研究,通过加双电层的水分子薄膜润滑与未加双电层薄膜润滑摩擦属性的对比,发现摩擦系数在存在双电层的情况下比未加双电层时要小,两板相对滑动速度对摩擦系数的影响与未加双电层时相似,相对滑动速度越大,摩擦系数在一定的速度范围内平稳增大.当速度大于某个数值时,摩擦系数增大变快.两板之间水分子以及离子密度或数目分布在靠近壁面的地方较大,中间密度相对较小.

Molecular dynamics （MD） simulations have been performed to do the test of the nanoscale friction properties for solution confined in charged and uncharged walls. By contrasting the friction properties of the water lubrication film confined in two Si walls with that in the wall having electric double layer,it is easily got that the friction coefficient is generally larger than that with electric double layer, and the influence on the friction coefficient of the relative motion velocity between two walls having electric double layer is similar, the larger the velocity is ,the larger the friction coefficient is when the velocity is in reasonable scope. But the friction coefficient increase largely when the velocity is beyond some scale. The density or the number of the water molecular and ions is large near the wall and small in the middle area of the nanoscale film of water.