Chen Ji, Hu Xue-Yi, Fang Yun, Liu Huan-Huan, Xia Yong-Mei
Key Laboratory of Synthetic and Biological Colloids (Ministry of Education); School of Chemical and Material Engineering , Jiangnan University , Wuxi , Jiangsu 214122 , P. R. China.
Langmuir. 2019 Feb 26;35(8):3116-3125. doi: 10.1021/acs.langmuir.8b04022. Epub 2019 Feb 13.
A series of novel anionic e-surfactants n-C P S was molecular designed and synthesized from long-chain fatty alcohols by polypropoxylation and sulfation followed by neutralization. Excellent all-round performance of extended surfactants (e-surfactants) interests us how a simple polypropylene oxide (PPO) spacer has great effects on properties. By a comparative study of conventional/ethoxylated/extended n-alkylsulfate surfactants, we were surprised to find that e-surfactants are in an obvious rugby shape at the air/water surface according to molecular surface area ( a), and it comes down to the intramolecular PPO spacer coiling and surface-induced collapse. On the basis of the interfacial properties of the e-surfactants, it is found that the PPO spacer can provide both hydrophilic and lipophilic contributions to an e-surfactant molecule. The synergism between PPO spacers and alkyl chains indicates that a certain PPO spacer can adjust the contributions in view of different alkyl chain lengths. Therefore, it is both the rugby-shaped molecular geometry of e-surfactants and the dynamic amphipathicity of a PPO spacer that makes e-surfactants behave with excellent interfacial and solution properties for household cleaning. Therefore, this work gives us a hint that the molecular geometry of surfactants plays a vital role in interfacial and solution properties similar to molecular amphipathicity.
通过对长链脂肪醇进行聚丙氧基化、硫酸化然后中和，分子设计并合成了一系列新型阴离子电子表面活性剂n-CPS。扩展表面活性剂（电子表面活性剂）出色的综合性能让我们思考一个简单的聚环氧丙烷（PPO）间隔基如何对性能产生巨大影响。通过对传统/乙氧基化/扩展的正烷基硫酸盐表面活性剂的对比研究，我们惊讶地发现，根据分子表面积（a），电子表面活性剂在空气/水表面呈明显的橄榄球状，这归因于分子内PPO间隔基的盘绕和表面诱导的塌陷。基于电子表面活性剂的界面性质，发现PPO间隔基可以为电子表面活性剂分子提供亲水性和亲脂性贡献。PPO间隔基与烷基链之间的协同作用表明，特定的PPO间隔基可以根据不同的烷基链长度调节贡献。因此，正是电子表面活性剂的橄榄球状分子几何形状和PPO间隔基的动态两亲性使得电子表面活性剂在家庭清洁中表现出优异的界面和溶液性质。因此，这项工作给我们一个提示，即表面活性剂的分子几何形状在类似于分子两亲性的界面和溶液性质中起着至关重要的作用。
