Vertical Orientation of Liquid Crystal on 4-n-Alkyloxyphenoxymethyl-Substituted Polystyrene Containing Liquid Crystal Precursor

We synthesized a series of polystyrene derivatives that were modified with precursors of liquid crystal (LC) molecules, such as 4-ethyloxyphenol (homopolymer PEOP and copolymer PEOP#; # = 20, 40, 60, and 80, where # indicates the molar fraction of 4-ethyloxyphenoxymethyl in the side chain), 4-n-butyloxyphenol (PBOP), 4-n-hexyloxyphenol (PHOP), and 4-n-octyloxyphenol (POOP), via polymer modification reaction to investigate the orientation of LC molecules on polymer films, exhibiting part of the LC molecular structure. LC molecules showed a stable and uniform vertical orientation in LC cells fabricated with polymers that have 4-ethyloxyphenoxymethyl in the range of 40-100 mol%. In addition, similar results were obtained in LC cells fabricated with homopolymers of PEOP, PBOP, PHOP, and POOP. The vertical orientation of LC molecules in LC cells fabricated with polymer films correlated to the surface energy of polymer films. For example, vertical LC orientation was observed when the total surface energies of the polymer films were lower than approximately 43.2 mJ/m(2). Good alignment stabilities were observed at 150 degrees C and 20 J/cm(2) of ultraviolet irradiation for LC cells fabricated with PEOP film.

Automated summary

A series of polystyrene derivatives modified with liquid crystal precursors were synthesized to investigate the orientation of LC molecules on polymer films, showing stable and uniform vertical orientation in LC cells fabricated with polymers containing a specific molar fraction of 4-ethyloxyphenoxymethyl. This study found that the vertical orientation of LC molecules in LC cells correlated with the surface energy of polymer films, and good alignment stability was observed under certain conditions.