Topological isomerism design of Demulsifiers: A fusion of molecular dynamics simulation and experiment

Demulsifiers are crucial for enhancing crude oil extraction and transportation efficiency by facilitating the separation of oil–water emulsions. However, research conducted on the design and synthesis of demulsifiers based on the results of molecular dynamics simulation remains scarce. Herein, we designed eight block polyethers, and explored their interfacial behaviors at the oil–water interface via molecular dynamics simulation. Correspondingly, eight block polyether demulsifiers were synthesized, and their interface properties were tested. The simulation results were consistent with the experimental results, indicating that the energy of simulation systems could be efficiently reduced by designed molecules, and that the prepared demulsifiers with the same structure could achieve effective demulsification correspondingly. Based on the simulation and experimental results, a "hand-shaped" demulsification mechanism model was proposed. The demulsifiers with hydrophobic "palm" and hydrophilic "fingers" demonstrated a more efficient performance in demulsification. The hydrophobic "palm" was stable in the continuous oil phase, and the hydrophilic "fingers" could attract dispersed water droplets to aggregate, facilitating demulsification. The study also finds that longer hydrophilic "fingers" exert stronger molecular force. Combining molecular dynamics simulation and experiment significantly accelerates the development of new demulsifiers, highlighting the utility of this approach in the research on demulsifiers.