Tilted <i>vs.</i> parallel assembly caused birefringent reversal in columnar phases of oligothiophene as well as applications for LEDs and hole transport materials.

ABSTRACT: Polycatenar columnar liquid crystals nT (n = 1-6) of π-conjugated oligothiophenes end-capped with bulky N-tris(hexadecyloxy)benzyl carbazole groups exhibit unusual molecular tilted and parallel assemblies, realizing the reversal of birefringence within the columnar liquid crystalline (LC) phases depending on core length and temperature. In the parallel arrangement of short core compounds 2T and 3T, molecules align perpendicular to the column axis. The stacking of these molecules involves a rotational component, resulting in local helical assembly, and this specific packing motif collectively stabilizes the Col_hex/p6mm phase with negative birefringence. In the tilted arrangement of long core compounds 5T and 6T, the long rigid core-driven tilted

SUBMITTER: Chen S 

PROVIDER: S-EPMC12369646 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature