近藤 瑞穂

Copolymer films of photoalignable liquid crystalline (LC) copolymethacrylates comprised of a phenyl benzoate mesogen connected with N-benzylideneaniline end moiety (NBA2) and benzoic acid (BA) side groups exhibit a photoinduced reorientation behavior. Significant thermally stimulated molecular reorientation attains a dichroism (D) greater than 0.7 for all copolymer films and a birefringence of 0.113–0.181. In situ thermal hydrolysis of the oriented NBA2 groups decreases the birefringence to 0.111–0.128. However, the oriented structures of the film are maintained, demonstrating a photo-durability, even though the NBA2 side groups photo-react. The hydrolyzed oriented films show higher photo-durability without changing their optical properties.

Photoinduced reorientation of composite films of liquid crystalline polymethacrylate comprised of benzoic acid (BA) side groups with different length alkylene spacer (PnBAM n = 2, 6, 10) and N-benzylideneaniline carboxylic acid (NBA) is investigated using linearly polarized (LP) 365 nm light. Significant thermally stimulated in-plane molecular orientation is attained when P6BAM (n = 6) is used, but higher amount of NBA is required for the in-plane reorientation of P2BAM (n = 2) films and out-of-plane motion of the BA side groups is observed for P10BAM (n = 10) films.

安息香酸（BA）側基を有するメタクリレートとn-ブチルメタクリレートからジブロック共重合体およびランダム共重合体を合成し、BAとのH結合を支配するN-ベンジリデンアニリンカルボン酸（NBA）をドープした薄膜の光誘起再配向を、直線偏光（LP）365nmおよび313nmの光を用いて調べた。BA側鎖の配向とNBAの昇華は、ジブロック共重合体フィルムでは熱刺激により十分に達成されたが、ランダム共重合体では熱処理によりランダム配向となった。さらに、NBAをドープしたフィルムにフォトマスクを用いてLP光を照射したときのフィルムの表面レリーフ（SR）形成について調べた。液晶特性、熱特性、軸選択的光異性化、フィルムの光架橋が、分子再配向とSR形成に重要な役割を果たしている。

Photoalignment of low-molecular-liquid crystalline (LC) cell is explored without surface treatment of the substrates. A linearly polarized (LP) light exposure to a LC cell containing nematic LCs and a small amount of photoresponsive material generates homogenous LC orientation of the cell. Material design, mixture ratio and exposure condition are investigated.