Liu Shasha, Yuan Shiling, Zhang Heng
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan 250100, China.
Molecules. 2022 Apr 15;27(8):2559. doi: 10.3390/molecules27082559.
A bidirectional pulsed electric field (BPEF) method is considered a simple and novel technique to demulsify O/W emulsions. In this paper, molecular dynamics simulation was used to investigate the transformation and aggregation behavior of oil droplets in O/W emulsion under BPEF. Then, the effect of surfactant (sodium dodecyl sulfate, SDS) on the demulsification of O/W emulsion was investigated. The simulation results showed that the oil droplets transformed and moved along the direction of the electric field. SDS molecules can shorten the aggregation time of oil droplets in O/W emulsion. The electrostatic potential distribution on the surface of the oil droplet, the elongation length of the oil droplets, and the mean square displacement (MSD) of SDS and asphaltene molecules under an electric field were calculated to explain the aggregation of oil droplets under the simulated pulsed electric field. The simulation also showed that the two oil droplets with opposite charges have no obvious effect on the aggregation of the oil droplets. However, van der Waals interactions between oil droplets was the main factor in the aggregation.
双向脉冲电场（BPEF）方法被认为是一种用于破乳O/W乳液的简单且新颖的技术。本文采用分子动力学模拟研究了BPEF作用下O/W乳液中油滴的转变和聚集行为。然后，研究了表面活性剂（十二烷基硫酸钠，SDS）对O/W乳液破乳的影响。模拟结果表明，油滴沿电场方向转变并移动。SDS分子可以缩短O/W乳液中油滴的聚集时间。计算了电场作用下油滴表面的静电势分布、油滴的伸长长度以及SDS和沥青质分子的均方位移（MSD），以解释模拟脉冲电场下油滴的聚集情况。模拟还表明，带相反电荷的两个油滴对油滴的聚集没有明显影响。然而，油滴之间的范德华相互作用是聚集的主要因素。
