Department of Electrical and Electronic Engineering, Southern University of Science and Technology , No. 1088, Xueyuan Road, Xili, Nanshan District, Shenzhen, Guangdong 518055, People's Republic of China.
School of Physics, Nankai University , Tianjin 300071, People's Republic of China.
Langmuir. 2017 Apr 25;33(16):3968-3974. doi: 10.1021/acs.langmuir.7b00417. Epub 2017 Apr 12.
Azobenzene photoalignment materials are highly effective for liquid crystal alignment with high sensitivity and rewritability. A strong relationship between relative humidity and the alignment quality of a thin layer of azobenzenesulfonic dye has been investigated, where the photoinduced phase retardation, order parameter, and anchoring strength of the alignment layer are influenced dramatically by relative humidity. Our results provide fabrication guidance for the photoalignment process in both display and photonic applications. In addition, an exotic substantial ordering enhancement is observed by increasing the relative humidity without further light illumination, where the self-assembly of the photoaligned material incorporated with water molecules is the underlying reason for the enhanced high ordering (S > 0.8). Based on X-ray diffraction and depolarized optical microscopy observation, together with the photoalignment quality, a semicrystalline structure of the humidified azobenzenesulfonic material is proposed. The transition from amorphous solid at low relative humidity to semicrystal at high relative humidity provides a new perspective of understanding the hydrophilic photoalignment materials.
偶氮苯光取向材料在液晶取向方面非常有效，具有高灵敏度和可重写性。本文研究了相对湿度与薄层偶氮苯磺酸染料取向质量之间的强关系，其中光致相位移、取向层的有序参数和锚定强度受相对湿度的显著影响。我们的研究结果为显示和光子学应用中的光取向过程提供了制造指导。此外，在没有进一步光照的情况下，通过增加相对湿度观察到一种奇特的实质性有序增强，其中掺入水分子的光取向材料的自组装是增强高有序性（S>0.8）的根本原因。基于 X 射线衍射和去偏振光学显微镜观察，以及光取向质量，提出了加湿偶氮苯磺酸材料的半晶结构。从低相对湿度下的无定形固体到高相对湿度下的半晶体的转变为理解亲水光取向材料提供了一个新的视角。
