Photosensitive bent-core liquid crystals based on methyl substituted 3-hydroxybenzoic acid

Abstract

Photosensitive liquid crystals are of contemporary interest not only from the scientific point of view but also for various applications. The chemical structure of materials is used to tune their mesomorphic and photosensitive properties.

Polar Order, Mirror Symmetry Breaking, and Photoswitching of Chirality and Polarity in Functional Bent‐Core Mesogens

“…The azobenzene unit involved in the molecular structures allows photoinduced isomerization of the azobenzene unit under UV irradiation (for solution spectra, see Figure S43 in the Supporting Information), which in turn can be used to modify the materials properties.P revious attempts of photoinduced switching with azobenzene-based BCLCs were based on at ransition of the antiferrolelectric B 2 or the B 7 phases into the isotropic liquid state, which reduces P s , [52,53] whereas here we report ap hotoswitching of the mode of switching under an Efield as well as an on/off switching of superstructural chirality.…”

“…[51] For this reason, azobenzene-basedB CLCs have attracted the attentiono fs everal researchers in recent years. [52][53][54][55][56][57][58][59][60][61] Compoundsw ith molecular shapes at the cross-over between linear (rod-like) and bent shapes( BCLCs), such as mesogenic dimers with odd spacers, [62][63][64][65][66][67][68][69] hockeys tick molecules, [70][71][72] and molecules with reduced length of the bent core [73] or with ar educed bending angle [74] have received significant attention, because they providen ew LC phase structures. 4-Cyanoresorcinol is av ery useful bent-core unit with reduced bending angle, which has led to an umber of new and unique mesophases, [37,38,[75][76][77][78][79][80][81][82] for example, the nontilted antiferroelectric SmAP A phase [83] and as hort-pitch heliconical smectic phase designatedasS mC s P F hel .…”

Photoswitching studies of new photochromic ionic liquids studied in real time by in situ irradiation

“…10 Molecular photoswitches have been successfully utilized as a powerful tool for developing new photoresponsive materials that have been used in several fields of chemistry, physics, and biology. Examples of these molecular devices are the multi-responsive drug release of azobenzene, 11 photosensitive liquid crystals, 12,13 photoresponsive block copolymers, 14 lightsensitive proteins for neuronal and cellular studies, [15][16][17] control of cellular mitosis, 18 photoisomerization-induced destabilization of b-DNA, 19 molecular information processing like molecular gates, 20,21 and more complex devices like adders/ subtractors and 22,23 encoders/decoders. 24,25 Usually azobenzene derivatives are covalently attached to an ionic liquid to modify their molecular properties and their potential applications.…”