Photoresponsive Stripe Pattern in Achiral Azobenzene Liquid Crystals

A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid-crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds.