Precipitation supramolecular complex for photoinduced anisotropic material with dual mesogenic units

A new family of dual-photoresponsive complexes has been fabricated based on the method of Precipitation Ionic Self-assembly (PISA). Poly (acrylic acid sodium salt) was coupled with two types of ionic mesogenic units containing azobenzene and cinnamate group, respectively, yielding a series of thermotropic liquid crystalline supramolecules. By changing the ratio of the two mesogenic units, different phase behaviors and nanostructures were obtained. Comparable photoinduced orientation of azo groups was observed in all the complex films after being irradiated by linearly polarized laser, while cinnamate groups can be crosslinked under UV light exposure. Furthermore, the influence of crosslinked cinnamate groups on the photoinduced orientation and its thermal stability was investigated in detail. This novel material may be utilized in many fields, such as surface relief gratings, liquid crystal display and nonlinear optics. This green and facial method can provide guidelines for the convenient design of multi-functional supramolecular materials.