Emergence of tilt in square honeycomb liquid crystals.

First liquid crystalline phases with tilted organization of rod-like aromatics in a square honeycomb structure were discovered. The developing tilt is temperature, chain length and chain volume dependent, and has a dramatic effect on the optical properties, occasionally leading to an inversion of birefringence. The observed effects of chain branching on tilt contributes to a general understanding of lateral chain engineering in tailoring the self-assembly of π-conjugated molecular rods.