Blue Luminescent Organic Light Emitting Diode Devices of a New Class of Star-Shaped Columnar Mesogens Exhibiting π–π Driven Supergelation

Five new, star-shaped compounds containing a central oligo(phenylenevinylene) core carrying six alkoxy chains were synthesized, and with varying alkyl chains the changes in their supramolecular assembly were explored by small and wide-angle X-ray scattering (SAXS/WAXS) studies. For the shortest peripheral alkoxy chain (3.1; R = 3,7-dimethyl octyl) lamellar stacking was favored, whereas with increasing the alkoxy chain length (3.2, 3.3, 3.4, and 3.5; n-C12H25, n-C14H29, n-C16H33, n-C18H35) columnar rectangular (Colr) assembly was observed. The compound with branched peripheral chains (3.1) with lamellar assembly did not exhibit organogelation, but four other compounds (3.2, 3.3, 3.4 and 3.5) showed the ability to gelate in nonpolar solvents at a lower concentration even in less than 1 wt % (qualifying it as a supergelator), possibly due to their existence in the Colr packing having strong π–π interactions. This occurrence is less observed, in comparison to previous reports where supergelation happened most...