Nanoparticle-doped polyimide for controlling the pretilt angle of liquid crystals devices.
The pretilt angles of liquid crystal molecules can be controlled by using conventional polyimide (PI) alignment material doped with different concentrations of Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticles, which have been observed to spontaneously induce vertical alignment. The addition of POSS in the homogenous PI changes the surface energy of the alignment layer and generates a variable pretilt angle. Experimental results demonstrate that the pretilt angle thetap is a function of the POSS concentration, and can be tuned continuously over the range of 0 degrees <thetap<90 degrees. The polar anchoring energy of POSS/PI alignment layer is almost constant regardless of the POSS concentration. This technique is very simple and is compatible with methods familiar in the current LCD industry.
Hwang
Shug-June
SJ
Department of Electro-Optical Engineering & Optoelectronics Research Center, National United University, Miao-Li 360, Taiwan.
Jeng
Shie-Chang
SC
Hsieh
I-Ming
IM
D004867:Equipment Design; D008027:Light; D050866:Liquid Crystals / Q000737:chemistry*; D053758:Nanoparticles; D012031:Refractometry / Q000295:instrumentation*; D012117:Resins, Synthetic / Q000737:chemistry*; D013499:Surface Properties
D012117:Resins, Synthetic; C029945:polyimide resin