Self-Alignment of Liquid Crystal Molecules on Polydiacetylene Langmuir-Blodgett Films

Abstract

Alignment structure and optical properties of Langmuir-Blodgett (LB) films of urethane-substituted polydiacetylene (poly-4BCMU) was investigated. During compression, the coil to rod transition in molecular conformation of poly-4BCMU was induced and the polymer main chains were aligned perpendicular to the compressing direction. The dichroic ratio of absorption intensity of poly-4BCMU monolayer film was about 6. LC molecules were sandwiched with two glass plates covered with the poly-4BCMU monolayer films. LC molecules aligned spontaneously along the main chain direction of poly-4BCMU in the parallel cell. On the other hand, they formed a twisted structure of 90° in the crossed cell. The monolayer film of poly-4BCMU had a high potential as rubbing-free alignment layer of LC molecules.

Keywords:

• liquid crystal
• polydiacetylene LB film
• self-alignment
• two-dimensional structure

Acknowledgments

This work was partially supported by a Grant-in-Aid for Scientific Research (16360040) and by the Photonics Materials Laboratory Project of the VBL of the Graduate School of Science and Technology, Kobe University.