Department of Chemistry and Biochemistry , University of Kitakyushu , 1-1 Hibikino , Kitakyushu , Fukuoka 808-0135 , Japan.
Langmuir. 2018 May 1;34(17):5072-5078. doi: 10.1021/acs.langmuir.8b00802. Epub 2018 Apr 19.
When the micellar aggregation number ( N) is small enough (<30), the N matches the value of vertexes of a regular polyhedron: Platonic solids, and demonstrates perfect monodispersity. These micelles are named Platonic micelles and are particularly found in the system of calix[4]arene-based micelles due to the rigid structure of the backbone molecule. Although sulfonatocalix[4]arene-based micelles are among the most studied host molecules in supramolecular chemistry, their micellar properties as Platonic micelles have thus far been overlooked. In this study, we prepared various sulfonatocalix[4]arene-based amphiphiles bearing alkyl chains with different lengths and investigated their aggregation behavior. When the amphiphiles formed spherical micelles, they demonstrated monodispersity in terms of N, whose value changed from 4 to 17, and then to 24, upon increasing the carbon number in each alkyl chain from C5 to C6, and then to C7, respectively. Although the numbers 17 and 24 do not match the vertices of regular polyhedra, these values can be reasonably explained by the Thomson problem, which considers the Coulomb potential for calculating the best packing on a sphere with multiple identical spherical caps. This study describes rediscovery of the monodispersity of sulfonatocalix[4]arene-based micelles, which is consistent with the idea of Platonic micelles.
当胶束聚集数 (N) 足够小 (<30) 时，N 与正多面体的顶点数匹配：柏拉图多面体，并表现出完美的单分散性。这些胶束被命名为柏拉图胶束，由于主链分子的刚性结构，特别存在于杯芳烃基胶束体系中。尽管磺化杯芳烃基胶束是超分子化学中研究最多的主体分子之一，但迄今为止，它们作为柏拉图胶束的胶束性质一直被忽视。在这项研究中，我们制备了各种带有不同长度烷基链的磺化杯芳烃基两亲分子，并研究了它们的聚集行为。当两亲分子形成球形胶束时，它们在 N 方面表现出单分散性，N 值从 4 变化到 17，然后分别增加每个烷基链中的碳原子数从 C5 到 C6，再到 C7，从 17 变为 24。尽管 17 和 24 不与正多面体的顶点匹配，但这些值可以通过汤姆森问题合理地解释，该问题考虑了计算带有多个相同球形帽的球体最佳堆积的库仑势。这项研究描述了磺化杯芳烃基胶束单分散性的重新发现，这与柏拉图胶束的思想一致。
