Ryohei Fukae

Preparation and Macroscopic Deformation of Liquid-Crystalline Polymer Fibers Crosslinked with Anthracene Side Chains

Anthraccene liquid-crystalline (LC) polymer fibers were synthesized and their photomechanical properties were explored. The polymer fiber bent toward a light source upon exposure to UV light due to photodimerization of anthracene moieties. They contracted with decrease in optical anisotropy along their fiber axis when they were heated above their LC-isotropic phase transition temperature.

Synthesis, characterization, and photoreaction of photoreactive liquid crystalline block copolyetheresters

Photo-crosslinkable thermotropic liquid crystalline block copolyetheresters with photoreactive hard segment of poly(hexamethylene p-phenylenediacrylate) and soft segment of poly(tetramethylene ether) were synthesized by melt polycondensation from n-butyl-p-phenylenediacrylate, hexamethylene glycol, and poly(tetramethylene ether) glycol ( PTMG, M n = 1000-3000). The influence of molecular weight and composition of PTMG unit on the thermal behavior was determined by differential scanning calorimetry and polarized optical microscopy. All synthesized block copolymers show thermotropic liquid crystalline phase and can photo-crosslink by UV irradiation. Photoreaction of the copolymer thin film was carried out using Hg-UV light and investigated by FT-IR spectroscopy and a dynamic viscoelastic analyzer.

Mechanoresponsive change in photoluminescent color of rod-like liquid-crystalline compounds and control of molecular orientation on photoaligned layer

In this paper, we reported novel liquid-crystalline luminophore that switches its photoluminescent color by mechanically grinding. Mechanochromic luminescence (MCL) is expected for mechanical sensor, cellular imaging, detection of microenvironmental changes, and optical memory. In this work, we focused on liquid-crystalline MCL compounds on alignment layer. Controlling the molecular alignment of MCL compounds with photoalignment layer have potential to succeed in functional MCL film such as polarized micropatterned MCL and directional detection of mechanical stimuli. Herein, we prepared asymmetric rodlike MCL compounds containing cyano- and pyridyl molecular terminal and explored their photoluminescence behavior under mechanical stimulus. The cyano terminated compound showed a nematic phase and tuned its photoluminescent color from green to yellow upon grinding, while the pyridyl-terminated compounds that show no mesophase changed its photoluminescent color from blue to green and reverted to its initial color by heating above its melting point. The cyano-terminated MCL was aligned along the orientation direction of photoalignment layer and pyridyl-terminated MCL exhibited uniaxial alignment when it coated on photoaligned film containing carboxylic acid.