Advanced Functional Materials, Vol.14, No.3, 247-254, 2004
Photogeneration of high pretilt angles of nematic liquid crystals by non-polarized light irradiation of azobenzene-containing polymer films
A vertical-alignment (VA) cell of nematic liquid crystals (LCs) was prepared using photoirradiated thin films of a poly(methacrylate) with mesogenic moieties of 4-trifluoromethoxyazobenzene as the side chains. Optical anisotropy was generated by oblique irradiation of the azobenzene-containing polymer films with non-polarized UV light, followed by annealing treatment to enhance the photodichroism, which displayed thermal stability. The combination of oblique exposure to non-polarized UV light and subsequent annealing treatment brought about high pretilt angles of nematic LCs so that a photoaligned VA LC cell was fabricated. The photopatterned LC cell exhibited electro-optical properties with excellent optical quality when a voltage was applied even after heating at 100degreesC for several hours.