Rational Route Toward the Frank-Kasper Z Phase: Effect of Precise Geometrical Tuning on the Supramolecular Assembly of Giant Shape Amphiphiles

Theoretically, 27 types of Frank-Kasper (FK) phases could be constructed with three cornerstones, the FK A15, C15, and Z phases. They are all spherical packing phases composed of spherical motifs. In single-component soft matter, the experimental observation(s) of the A15 phase is common while C15 and Z phases are rare. Recently, a serendipitous observation of an FK Z phase with significant volume asymmetry of the constructing spherical motifs from a giant shape amphiphile assembly has been reported. In single-component soft matter, it is anticipated that the significant volume asymmetry of spherical motifs consisting of mu and mu +/- 1 molecules could be readily reached when the mu is small. Herein, we present a design strategy to precisely control the number of molecules inside a spherical motif by geometrical tuning of the molecular building blocks, thus leading to the formation of the FK Z phase in a rational manner.