Synthesis and Electro-Optical Studies on Composite Material: Functionalized Copolymer Particles/Nematic Liquid Crystal

Abstract

We have synthesized new functionalized copolymers of the type divinyl benzene – maleic anhydride (DVB-MA) in order to ensure a better compatibility with the penthyl-phenol group of the liquid crystal. These particles have been mixed by stirring and ultrasound with nematic liquid crystals ZLI 1221 (Merck), concentration 5% b.w. (copolymer/LC). We applied cycles of temperature and electric field, corresponding to the TSDC method. We measured the depolarization currents and simultaneously the optical transmission as a function of the electric field and temperature. We obtained information regarding the conduction mechanism, the distribution of the activation energy and the influence of the polarizing voltage on the optical transmission.

Keywords:

• functionalized copolymers
• liquid crystal colloidal composites
• optical transmission
• TSDC

Acknowledgments

The author acknowledges the Romanian Ministry of Education and Research for financial support under the CEEX program, Project CEX-05-D11-76, and the Merck Company for providing the liquid crystal. We thank Marius Ghiurea (ICECHIM) for providing the SEM picture.