Photoinduced circular anisotropy in a photochromicW-shaped-molecule-doped polymeric liquid crystal film

Abstract

Photoinduced circular anisotropy has been demonstrated in thin films of a main-chain polymeric liquid crystal (PLC) system doped with photochromic W-shaped molecules containing two azobenzene groups by irradiating with circularly polarized light (CPL). Reversible photoinduced circular dichroism (CD) was observed with sign relevant to the handedness of the CPL. The experimentally observed CD spectra were analyzed using the DeVoe polarizability model associated with the coupled oscillator method. We also propose a mechanism for the photoinduced circular anisotropy in our system; nucleating the W-shaped molecules with preferential twisted conformation by CPL irradiation, and triggering the local formation of a chiral structure in the W-shaped-molecule-doped main-chain PLC medium.

Reversible Photoinduced Chiral Structure in Amorphous Polymer for Light Polarization Control

“…The published results suggest that the phenomenon occurs when a macroscopic linear anisotropy is present in the light or in the medium. 21,30,32,34,[36][37][38][39] The experimental investigation reported here demonstrates that even in an amorphous, nonchiral polymer film without any prealignment, a CPL beam can induce a reorganization of the material related to the light chirality. The new structure of the material strongly affects the polarization state of the light propagating in it.…”

Light‐Driven Supramolecular Chirality in Propeller‐Like Hydrogen‐Bonded Complexes That Show Columnar Mesomorphism

“…[9] Moreover, supramolecular chirality photoinduced by CPL has been reported in azopolymers [10] and in main-chain polymeric liquid-crystal systems doped with azobenzene-containing W-shaped molecules. [11] However, attempts to induce supramolecular chirality in columnar mesophases formed by azobenzene-containing mesogens have not been described to date. We demonstrate herein the possibility of controlling the supramolecular chirality of a helical stack of propeller-like complexes using an external chiral stimulus such as CPL.…”

Chirality Induced by Circularly Polarized Light in Liquid Crystalline Twin Dimers with Azo Linkages

“…One of the conventional methods is the use of circularly polarized light (CPL). This method has been employed to induce chirality in many soft materials such as polymers and liquid crystals [1][2][3][4][5][6][7][8][9]. The materials have to possess photoisomerizable groups such as azobenzene and stilbene.…”