Yoshimura Tomokazu, Yoshida Hiroaki, Esumi Kunio
Research Group of Chemistry, Division of Natural Science, Nara Women's University, Nara, Japan.
J Oleo Sci. 2013;62(9):673-80. doi: 10.5650/jos.62.673.
Multichain amide-bonded anionic amphiphilic oligomers consisting of dodecyl acrylamide and sodium acrylate (i.e., xC₁₂AAm-yAA, where x and y represent the number of dodecyl acrylamide (C₁₂AAm) and sodium acrylate (AA) units, respectively) were synthesized via the radical oligomerization of two monomers in the presence of 2-aminoethanethiol hydrochloride. Equilibrium and dynamic surface tension, pyrene fluorescence, dynamic light scattering, and steady-state fluorescence quenching measurements were used to characterize the properties of the oligomers. In addition, the effects of the polymerization degree and number of dodecyl chains and hydrophilic groups on these properties were evaluated via comparison of these results with those of previously reported amphiphilic oligomers with ester bonds and conventional anionic monomeric surfactants. xC₁₂AAm-yAA exhibits lower critical micelle concentration (cmc) values than conventional sodium n-dodecanoate surfactant, indicating their excellent micelle-forming ability despite the large molecular structure with a long polymer main chain. The 3.0C₁₂AAm-7.5AA oligomer features the lowest cmc. The surface tensions of xC₁₂AAm-yAA at the cmc are lower than those of the conventional surfactant, which indicates that the oligomers adsorb and orient efficiently at the air-water interface. Further, xC₁₂AAm-yAA forms small aggregates with diameters of ~10 nm and aggregation numbers of 2-8 as well as large aggregates composed of masses of small aggregates. An increase in the polymerization degree of the oligomers decreases the aggregation number of the small aggregates; this indicates that it is more difficult for oligomers with long polymer chains to form aggregates due to their bulky structure.
由十二烷基丙烯酰胺和丙烯酸钠组成的多链酰胺键合阴离子两亲性低聚物（即xC₁₂AAm - yAA，其中x和y分别代表十二烷基丙烯酰胺（C₁₂AAm）和丙烯酸钠（AA）单元的数量）是在2-氨基乙硫醇盐酸盐存在下通过两种单体的自由基低聚反应合成的。通过平衡和动态表面张力、芘荧光、动态光散射和稳态荧光猝灭测量来表征低聚物的性质。此外，通过将这些结果与先前报道的具有酯键的两亲性低聚物和传统阴离子单体表面活性剂的结果进行比较，评估了聚合度、十二烷基链数量和亲水基团对这些性质的影响。xC₁₂AAm - yAA表现出比传统正十二酸钠表面活性剂更低的临界胶束浓度（cmc）值，表明尽管其具有长聚合物主链的大分子结构，但仍具有优异的胶束形成能力。3.0C₁₂AAm - 7.5AA低聚物的cmc最低。xC₁₂AAm - yAA在cmc时的表面张力低于传统表面活性剂，这表明低聚物在空气 - 水界面上能有效吸附并定向排列。此外，xC₁₂AAm - yAA形成直径约为10 nm、聚集数为2 - 8的小聚集体以及由大量小聚集体组成的大聚集体。低聚物聚合度的增加会降低小聚集体的聚集数；这表明具有长聚合物链的低聚物由于其庞大的结构更难形成聚集体。
