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PECULIAR ORIENTATION OF NEMATIC LIQUID CRYSTALS ON RUBBED POLYVINYLIMIDAZOLE

S. Frunza1,* , T. Beica1, R. Moldovan1,2, I. Zgura1, L. Frunza1

Affiliation

  1. National Institute of Materials Physics, Bucharest-Magurele, Romania
  2. Romanian Academy Center of Advanced Studies in Physics, Bucharest

Abstract

Alignment properties of rubbed films of polyvinyl imidazole were studied by observing with the polarizing microscope the features of the nematic liquid crystal (LC) droplets onto these layers. It was found that the observing of the droplets can reveal the direction of easy axis on the alignment substrate not only in the case of LC having the director normal to the LC/air interface but also in the case of the director tangent to this interface, when no disclination line could be seen. We observed that some of the LCs are oriented parallel to the rubbing direction, but the other LCs are perpendicularly oriented. This peculiar behavior is at variance to that found on rubbed layers of polyvinyl alcohol. The role of the end-groups in the structure of the LCs on the alignment properties is discussed..

Keywords

Nematic liquid crystals, Alignment layers, Rubbed polyvinyl imidazole, Cyan end-group, Methoxy end-group.

Submitted at: July 4, 2005
Accepted at: July 21, 2005

Citation

S. Frunza, T. Beica, R. Moldovan, I. Zgura, L. Frunza, PECULIAR ORIENTATION OF NEMATIC LIQUID CRYSTALS ON RUBBED POLYVINYLIMIDAZOLE, Journal of Optoelectronics and Advanced Materials Vol. 7, Iss. 4, pp. 2149-2157 (2005)