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Surface anchoring, polymer glass transition, and polymer-dispersed liquid crystal electro-optics

  • John L. West
  • , Keith Jewell
  • , James Francl
  • , Yimin Ji
  • , Jack R. Kelly

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

9 Scopus citations

Abstract

We studied the electro-optic properties as a function of temperature of a PDLC film composed of either E7 or E43 dispersed as droplets in a polyvinylformal (PVFM) matrix. The dissolved liquid crystal lowers the glass transition temperature, Tg, of the PVFM matrix to about 30 - 35°C. The electro-optics of these PDLC films change abruptly at the polymer matrix Tg. In general the drive voltage decreases and the turn off time increases rapidly as the temperature is raised above Tg. Also, the shutter has essentially no hysteresis below, and significant hysteresis above Tg. These temperature effects are completely reversible. The rapid change in electro-optic properties cannot be entirely explained by changes in the polymer dielectric properties or droplet size and shape. We have therefore postulated that changes in the surface anchoring energy of the liquid crystal are primarily responsible for the abrupt changes in the electro-optic response at the matrix Tg.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherPubl by Society of Photo-Optical Instrumentation Engineers
Pages8-12
Number of pages5
ISBN (Print)0819408190
StatePublished - 1992
EventProceedings of the Conference on Liquid Crystal Materials, Devices, and Applications - San Jose, CA, USA
Duration: Feb 11 1992Feb 13 1992

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1665
ISSN (Print)0277-786X

Conference

ConferenceProceedings of the Conference on Liquid Crystal Materials, Devices, and Applications
CitySan Jose, CA, USA
Period02/11/9202/13/92

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