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采用非平衡态分子动力学法对纳米胶体及其溶液环境进行建模,通过对模型系统施加非均匀电场,使胶体带有相反的极性.在较高的电场强度和较低的系统温度情况下介电泳驱动胶体分离的现象较为明显,对胶体的介电泳速度与溶剂粒子热运动速度比值进行研究,发现比值较大时,胶体与溶剂粒子的撞击较为剧烈,使得胶体的速度出现大幅度的波动.改变电场强度进行模拟,发现电场强度的增大能加快胶体的分离,但当电场强度增大到一定程度时,由于溶剂粒子对胶体的摩擦阻力很大,使得分离运动开始变慢.此外,在分析胶体位能的基础上研究胶体的分离原因,发现胶体电偶极化后胶体之间的吸引位能变小,而温度的升高使得吸引位能变小,排斥位能增大,这与DLVO理论得出的结论相一致.
The non-equilibrium molecular dynamics method was used to model the environment of nanocolloids and their solutions by applying a non-uniform electric field to the model system to reverse the polarity of the colloids. At higher electric field intensities and lower system temperatures The phenomenon of colloid separation driven by the dielectrophoresis is obvious. The ratio of the dielectrophoretic velocity to the thermal kinetic velocity of the solvent particle is studied. It is found that when the ratio is larger, the collisions between the colloid and the solvent particle are more violent, resulting in a significant It is found that the increase of electric field can accelerate the separation of colloids, but when the electric field strength increases to a certain degree, the separation resistance begins to slow down because of the great frictional resistance of solvent particles to colloids. Based on the analysis of the potential energy of colloids, the reasons for the separation of colloids were studied. It was found that the attraction between colloids could be reduced after the colloidal electric dipolarization. The increase of temperature made the attraction less and the exclusion potential increased, This is consistent with the conclusion of DLVO theory.