The Structural Effects on the Pretilt Angle of Alignment Materials with Alkylcyclohexylbenzene as a Side Chain in Polyimides

ABSTRACT

We have investigated the relationship between the surface property of rubbed polyimides and the variation of pretilt angle according to the side chain and main chain structures. We calculated the surface free energy of synthesized polyimide surface by measuring the contact angles of distilled water and methylene iodide on the rubbed polyimide surface. Consequently, we found that pretilt angles on rubbed polyimides changed according to the side chain and main chain structures of the polyimide. Our calculations show that LC pretilt angles of polyimide films with a liquid crystal structure as a side chain were approximately 90° when a linear and rigid polyimide main chain and a side chain of suitable length were employed.

Keywords:

• alignment materials
• liquid crystal
• pretilt angle
• side chain type polyimide
• surface free energy

Acknowledgments

Authors thank Dong-Jin Semichem Co., Ltd. for their financial support for this study.

Notes

^a After the molecular conformation obtained by using MM2 of Chem 3D ultra 7.0, each length is calculated.