School of Food and Chemical Engineering, Beijing Technology and Business University, Beijing 100048, P. R. China.
Soft Matter. 2019 Jan 28;15(4):699-708. doi: 10.1039/c8sm02383b. Epub 2019 Jan 9.
The present study was conducted to investigate the effects of the strong van der Waals interaction and sterol skeleton of surfactants on their interfacial rheological behaviors by comparing the interfacial properties of sodium cholesteryl glycylglycine (Chol-GG-Na) and sodium lauryl glycylglycine (C12-GG-Na) at the oil-aqueous interface. The interfacial dilational rheological experiment results indicate a significant increase in the interfacial activity and intermolecular interaction with the introduction of the cholesteryl group. Therefore, a compact interfacial layer with a remarkably high dilational modulus was obtained with the adsorption of Chol-GG-Na. The cholesteryl group also has a significant impact on the dynamic processes such as it slows down the motion of the molecules due to which the diffusion exchange between the bulk and the interface decreases. Besides, the rigid skeleton makes rearrangement and conformation adjustment difficult. These impacts become more pronounced when the adsorption layer approaches a close and ordered arrangement, which has been confirmed by the relaxation measurements. The reported results provide a theoretical foundation for the potential applications of cholesteryl-based surfactants in the food, pharmaceutical, cosmetic and petroleum industries.
本研究通过比较胆固醇基甘氨酰甘氨酸（Chol-GG-Na）和十二烷基甘氨酰甘氨酸（C12-GG-Na）在油水界面上的界面性质，研究了强范德华相互作用和表面活性剂甾醇骨架对其界面流变行为的影响。界面扩张流变实验结果表明，引入胆固醇基后，界面活性和分子间相互作用显著增加。因此，Chol-GG-Na 的吸附可获得具有高扩张模量的紧密界面层。胆固醇基还对分子的动态过程产生显著影响，由于其阻碍了主体和界面之间的扩散交换，从而减慢了分子的运动。此外，刚性骨架使重排和构象调整变得困难。这些影响在吸附层接近紧密有序排列时更为明显，弛豫测量已经证实了这一点。所报道的结果为基于胆固醇的表面活性剂在食品、制药、化妆品和石油工业中的潜在应用提供了理论基础。
