Controlling spontaneous mirror symmetry breaking in cubic liquid crystalline phases by the cycloaliphatic ring size.

Rod-like molecules combining a fork-like triple chain end and a cycloaliphatic apex are introduced as a new design concept for materials with broad ranges of bicontinuous cubic (Cub(bi)) phases. By ring expansion from n = 4 to 12 a sequence of three Cub(bi) phases is observed; the achiral double gyroid la3d phase, a chiral "Im3m" phase and an achiral re-entrant la3d phase. The chiral "Im3m" phase is formed if the helical twist between the molecules along the networks is in the range of 8.6 degrees-9.5 degrees, either for the individual compounds or their mixtures.