Fabrication of a new homeotropic alignment layer for nematic liquid crystals using an in situ self-assembly of alkylated benzoic acid derivative

ABSTRACT

We have presented a novel vertical alignment method simultaneously enhancing the alignment ability and electro-optical performances of nematic liquid crystals (LCs). The method relies on the self-assembly of 4-(4-heptylphenyl)benzoic acid and 2-carboxyethyl acrylate through hydrogen bonding with conventional polyimide and the generation of pre-tilting in the LC molecules using ultraviolet irradiation under applied voltage. The electro-optical measurements of a LC device fabricated by using this self-assembled polyimide layer exhibited strong homeotropic alignment and fast response time. The proposed alignment method may be valuable in providing new functional alignment materials for high-performance LC devices.

KEYWORDS:

• Homeotropic alignment
• hydrogen bonding
• liquid crystal display
• polyimide
• self-assembly

Funding

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