A Photochromic Main-Chain Liquid Crystalline Polymer and Its Photo-Stimulated Actuating Properties

摘要

To explore novel photoresponsive liquid crystalline polymer actuator, a new difunctional photosensitive nematic liquid crystalline monomer was synthesized synthesized in high yield (>60% overall), and polymerized via acyclic diene metathesis polymerization (ADMET) method. Nematic monomer, 4-butoxy-2'-(4-hex-5-enyloxy)-4'-(4-hex-5-enyloxybenzyloxy)-azobenzene, exhibited crystalline to nematic and nematic to isotropic transitions at 85.6 and 98.3 ℃, respectively. ADMET polymerization of the monomer using Grubbs catalyst (Gen II) was performed to obtain a high molecular weight polymer. Brown colored free-standing polymer film and fiber were prepared from casting chloroform solution or from drawing polymer melt, respectively. The polymer film showed nematic liquid crystalline property with photosensitive phase transition behavior as observed by polarized microscope and differential scanning calorimetry. The photomechanical deformation of the film and fiber induced by polarized UV irradiation was investigated.