Open AccessIsothermal electrically and optically induced phase separation of liquid crystal and poly(N-vinylcarbazole) films
Author(s) -
YenChen Liu,
ChengKai Liu,
Andy Ying–Guey Fuh
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.021004
Subject(s) - materials science , isothermal process , isomerization , liquid crystal , phase (matter) , relaxation (psychology) , optics , phase transition , optical transparency , light scattering , optoelectronics , scattering , condensed matter physics , thermodynamics , chemistry , organic chemistry , catalysis , psychology , social psychology , physics
This paper reports the electro- and photo-isomerization-induced isothermal phase separation of liquid crystals (LCs) and poly(N-vinylcarbazole) (PVK). The proposed phase separation process determines reformed PVK films on substrates to obtain switchable LC light valves. UV illumination induces simultaneous isothermal phase transition of the mixture and dissolution of PVK into the LCs. Phase separation of PVK and LCs occurs by the reversed phase transition via rapid electro-isomerization and slow dark-relaxation. During rapid phase separation, micron-sized LC domains (branch-like PVK structures) are generated to develop stable light scattering; during slow dark-relaxation, a uniform PVK film is obtained, thereby providing stable transparency.