阴离子Gemini表面活性剂在油/水界面行为的分子动力学模拟

采用分子动力学方法研究了磺酸盐型阴离子Gemini表面活性剂在油/水界面的吸附行为, 考察了不同长度的连接基(Spacer)对表面活性剂在界面的聚集形态及界面性质的影响. 密度分布和微观结构信息显示, Gemini表面活性剂能在油/水界面形成单层膜结构. Gemini表面活性剂能使油/水界面的厚度显著增大, 并使界面形成能降低. 当连接基为6个碳时, 此类磺酸盐型Gemini表面活性剂的界面厚度最大, 形成的界面最稳定. 连接基长度对Gemini表面活性剂单层膜周围的水分子和Na⁺的吸附结构影响不大, 但是能影响水分子的扩散行为.

Molecular Dynamics Simulation on Adsorbing Behavior of Anionic Gemini Surfactants at Decane/Water Interface

Molecular dynamics simulations were performed to investigate the adsorbing behavior of anionic sulfonate Gemini surfactants at oil/water interface.Effects of spacer on the aggregation and interfacial properties of surfactants were studied in detail.The interfacial structure and density profiles of adsorbents show the exis-tence of Gemini surfactants monolayer.The interfacial thickness increased significantly and the interface formation energy decreased when incorporating the Gemini surfactants into the oil/water interface.Better interfacial properties are also found in this work when the spacer has six carbons.Except for water molecular diffusion properties,only little effect of spacer on the adsorbing structure and properties of water and Na+ surroun-ding the interface of Gemini surfactants are found.