Open AccessOptical manipulation of the nematic director field around microspheres covered with an azo-dendrimer monolayer
Author(s) -
Pemika Hirankittiwong,
Nattaporn Chattham,
Jumras Limtrakul,
Osamu Haba,
Koichiro Yonetake,
Alexey Eremin,
Ralf Stannarius,
Hideo Takezoe
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.22.020087
Subject(s) - dendrimer , azobenzene , liquid crystal , materials science , optics , microparticle , ultraviolet , microsphere , optoelectronics , nanotechnology , chemical engineering , polymer chemistry , polymer , composite material , physics , engineering
We report here the optical manipulation of the director and topological defect structures of nematic liquid crystals around a silica microparticle with azobenzene-containing dendrimers (azo-dendrimers) on its surface. We successfully demonstrate the successive switching processes from hedgehog, to boojum, and further to Saturn ring configurations by ultraviolet (UV) light irradiation and termination. The switching time between these defect structures depends on the UV light intensity and attains about 50 ms. Since the pretreatment of microparticles is not necessary and the surface modification is spontaneously performed just by dissolving the azo-dendrimers in liquid crystals, this dendrimer supplies us with a variety of possible applications.