Stable vertical alignment of liquid crystals by using an in situ self-assembly of 4-(4-heptylphenyl)benzoic acid

ABSTRACT

In this study, the enhanced vertical alignment of liquid crystals (LCs) was achieved by the in situ self-assembly of 4-(4-heptylphenyl)benzoic acid in the LC cell. The self-assembled alignment layer forms via hydrogen bonding between 4-(4-heptylphenyl)benzoic acid as a functional alignment agent and the conventional polyimide in the LC media. The LC cell fabricated using LC mixture doped with low concentrations of the alignment agent afforded good and uniform vertical alignment of LC molecules. The electro-optical characteristic of the proposed LC cell exhibited better homeotropic alignment than that of LC cell with conventional polyimide layer.

KEYWORDS:

• Hydrogen bonding
• LCD
• polyimide
• self-assembly
• vertical alignment

Funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2014R1A1A2057947).