通过两次光照法制备了一种基于共价键结构的自组装光控取向膜。首先采用重氮树脂与聚(4-丙烯酰氧基肉桂酸(4′-磺酸钠)苯酚酯)在水溶液状态下通过静电离子沉积法制备了layer-by-layer型的自组装多层膜,制备过程的紫外-可见光谱表明薄膜为逐层、均匀沉积。第一次光照将膜层间的重氮磺酸盐离子键转化为共价键结构,然后采用线性偏振紫外光进行第二次光照,获得具有各向异性的光控取向膜。紫外-可见光谱法证实了薄膜辐照过程中的光化学反应方式。这种液晶光控取向膜可以水平均匀取向向列相液晶,而且具有良好的热稳定性,可达到150℃。
A covalently attached photoalignment film based on self-assembled multilayer film was prepared by twice irradiation of UV light. A layer-by-layer film was fabricated from poly (4-sulfonic phenoxy (4-acrloyloxy) cinnamate, sodium salt) and diazoresin in aqueous solution via electrostatic attraction. The UV-Vis spectra of multilayer film with different number of layers proved that the film was uniform and layer-by-layer. The ionic bonds in the film between sulfonate ions and diazonium ions were converted into covalent bonds under 365 nm UV irradiation. The covalently attached self-assembled film was irradiated by linearly polarized UV light, and exhibited anisotropy. The photoalignment film could induce uniform alignment of liquid crystal in planar state, and showed good thermal stability(〉 150℃).