Polymers have a significant impact on the electrostatic demulsification efficiency of water-in-oil (W/O) emulsions by altering the motion characteristics of water droplets. To uncover the underlying micro-mechanism behind electric field-induced deformation and breakup of polymer-containing water droplets, we employed the molecular dynamics (MD) method to investigate the effect of different polymer concentrations (c_p) on droplet motion under a DC electric field. The simulation results indicated that polyacrylamide (PAM) molecules possess a prominent electrostatic potential (ESP), resulting in a strong electrostatic attraction between PAM and water. The interface film of the droplet was found to exhibits high strength due to the formation of hydrogen bonds with a lifetime of 1 ps between polymers. The addition of polymers increased the polarity of the droplets, thereby promoting their deformation and breakup under an electric field. Both polarized polymers and ions migrated by carrying water molecules, which ultimately led to droplet breakup. At c_p = 0.0221 mol·L⁻¹, the critical field strength (E_c) for droplet breakup was the lowest, at only 0.672 V·nm⁻¹. As c_p > 0.0221 mol·L⁻¹, the steric hindrance of PAM molecules and the strong interfacial film impeded the breakup of the droplets. These findings provided a theoretical basis for enhancing the electrostatic demulsification efficiency of polymer-flooding crude oil.

聚合物通过改变水滴的运动特性对油包水 (W/O) 乳液的静电破乳效率产生重大影响。为了揭示电场诱导含聚合物水滴变形和破碎背后的潜在微观机制，我们采用分子动力学 (MD) 方法研究了不同聚合物浓度的影响 ( c _p）在直流电场下的液滴运动。模拟结果表明，聚丙烯酰胺 (PAM) 分子具有显着的静电势 (ESP)，导致 PAM 和水之间产生强烈的静电吸引力。由于在聚合物之间形成了寿命为 1 ps 的氢键，液滴的界面膜被发现表现出高强度。聚合物的添加增加了液滴的极性，从而促进了它们在电场下的变形和破碎。极化聚合物和离子都通过携带水分子迁移，最终导致液滴破裂。在c _p  = 0.0221 mol·L ⁻¹时，临界场强 ( E _c) 液滴破裂最低，仅为 0.672 V·nm ^-1。当c _p  > 0.0221 mol·L ^-1时，PAM分子的位阻和强界面膜阻碍了液滴的破碎。这些研究结果为提高聚合物驱原油静电破乳效率提供了理论依据。