Effect of prepolymer structure on the electro-optic performance of polymer dispersed liquid crystals

✍ Scribed by Kim, Seon Hee; Heo, Chong Phil; Park, Kwan Sun; Kim, Byung Kyu

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 477 KB
• Volume: 46
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199806)46:2<143::aid-pi979>3.0.co;2-z

✦ Synopsis

The e †ect of prepolymer structure on the electro-optic properties of polymer dispersed liquid crystals (PDLCs) prepared from UV-cured polyurethane acrylates (PUAs) has been studied. Among four types of Ðlms with di †erent soft-segment structure, polypropylene glycol (PPG)-and polytetramethyl ether glycol (PTMG)-based PUAs gave lower threshold and (V 10 ) operating voltages, whereas polycaprolactone diol (PCL)-based PUAs gave (V 90 ) higher and voltages. The use of mixed polyol polypropylene glycol/ V 10 V 90 poly(tetramethylene adipate)diol) (PPG/PTAd) gave an electro-optic response intermediate between the two. Regarding the e †ect of hard segment type, that from a linear aliphatic diisocyanate (hexamethylene diisocyanate, HDI) gave the lowest and voltages as well as transparentÈtranslucent transition tem-V 10 V 90 perature compared with those from cycloaliphatic diisocyanates. This was interpreted in terms of a more Ñexible nature and hence a lower glass transition temperature of HDI-based PUA.

1998 SCI.