Title :
Phase separation and pattern instability of laser-induced polymerization in liquid-crystal-monomer mixtures
Author :
Jisha, Chandroth P. ; Hsu, Kuei-Chu ; Lin, YuanYao ; Lin, Ja-Hon ; Chuang, Kai-Ping ; Tai, Chao-Yi ; Lee, Ray-Kuang
Author_Institution :
Inst. of Photonics Technol., Nat. Tsing-Hua Univ., Hsinchu, Taiwan
Abstract :
Directly written by a ultra-short femto-second laser pulse, we report the phase separation and pattern formation induced by polymerization in a liquid-crystal-monomer mixture. By varying the scanning speed of optical fields along a line, pattern transitions of photon-induced polymer structures are illustrated in shapes of double-humped, single-humped, and broken stripes. The optical microscope images taken in experiments are in a good agreement with numerical simulations based on a modified set of coupled 2 + 1 dimensional diffusion equations. The demonstration in this work provides a step for controlling phase separation morphologies as well as transferring patterns in polymer-dispersed liquid crystals.
Keywords :
high-speed optical techniques; laser materials processing; optical microscopy; optical polymers; pattern formation; phase separation; polymer dispersed liquid crystals; polymer structure; polymerisation; broken stripe shapes; double-humped shapes; laser-induced polymerization; liquid-crystal mmonomer mixtures; optical fields; optical microscope; pattern formation; pattern instability; pattern transitions; phase separation morphologies; photon-induced polymer structures; polymer-dispersed liquid crystals; scanning speed; single-humped shapes; ultrashort femtosecond laser pulse; Biomedical optical imaging; Liquid crystals; Morphology; Optical polymers; Optical pulses; Ultrafast optics;
Conference_Titel :
Lasers and Electro-Optics (CLEO), 2012 Conference on
Conference_Location :
San Jose, CA
Print_ISBN :
978-1-4673-1839-6
