A series of calix[4]arene-based lipids with alkyl chains of varying length were newly synthesized and found that some of them form spherical micelles with a defined aggregation number. These aggregation numbers are 6, 8, 12, and 20, interestingly coinciding the numbers of the Platonic solids. Synchrotron small-angle X-ray scattering (SAXS) patterns exhibited a sharp intensity minimum, indicating high symmetry and shape monodispersity. The size monodispersity of the micelles was confirmed with analytical ultracentrifugation and asymmetric filed flow fractionation. The present results indicate that a suitable combination of tail length, head volume, and rigidity of the building block is necessary to attain the shape persistency. With a shape determination program of Dummy and molecular dynamics calculation, the micellar architecture was determined and an atomic scale model to reproduce SAXS profile was constructed.<br/>We have a hypothesis that can rationalize why the aggregation numbers are taking such a discreet manner and chosen from the numbers of the Platonic solids; the aggregation number is determined by the J. J. Thomson’s theorem to determine the minimum electrostatic potential energy configuration of N electrons on the sphere surface that repel each other. We suppose this can be extended to the other spherical micelles when the aggregation numbers are small enough.

Shape persistence micelles having the same aggregation numbers with the platonic solids

251st National Meeting (2016)

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