New Strategies for Light-Induced Alignment and Switching in Liquid Crystalline Polymers
The photoalignment processes in liquid crystal films are based on the occurrence of angular selective photoreactions by linearly polarized light or oblique incidence of light. Alignment of nematic liquid crystals by a surface photoreactive layer has recently become of industrial importance in the fabrication of liquid crystal display panels due to the advantages of non-contact and fine resolution processing. Efforts in this field have also been extending to develop other types of procedures with various liquid crystalline materials. This chapter introduces some new trends in the photoalignment studies including systems of (i) lyotropic chromonic and organic–inorganic hybrids, (ii) block copolymer systems, and (iii) new methods utilizing the free (air) surface for inducing the alignment. These new strategies are expected to provide new directions of materials chemistry and phototechnologies.
KeywordsPhotoalignment Polarized light Azobenzene Organic–inorganic hybrids Block copolymers Free surface
Grazing incidence—small angle X-ray scattering
Polarized optical microscopy
We thank the collaborators and students for their great efforts to the research projects. The projects described here were supported from the Grants-in-Aid for Scientific Research on Priority Area “New Frontiers in Photochromism” (471) and “Photosynergetics” (15H01084) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Grant-in-Aid for Scientific Research (S) (23225003) to TS, and (B) (25286025) to SN, and the Grant-in-Aid for Young Researcher (B) (25810117) to MH of the Japan Society for the Promotion of Sciences (JSPS). The synchrotron in situ X-ray measurements was conducted at Tsukuba KEK-Photon Factory (proposal No. 2012G629), and we are greatly indebted to Profs. Y. Amemiya and Y. Shinohara of the University of Tokyo in these measurements.
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