Comparison of photoinduced reorientation of ortho-, meta-, and para-methyl red-doped nematic liquid crystals on rubbed polyimide
Persistent URL
Author(s)
Statman, David
Statman, Ariel T.
Wozniak, Kaitlin
Brennan, Christopher
Date Issued
August 28, 2015
Abstract
We compare the photoinduced reorientation of the easy axis on rubbed polyimide surfaces for the nematic E7 doped with three isomers of methyl red; ortho, meta, and para. Using optical techniques, the angle and the pitch of the director at the polymer surface were measured before, during, and after photoexcitation of the dye. Optical absorbances were also measured before and after photoexcitation. Extrapolation lengths, hence anchoring energies, were determined with the on/off application of a magnetic field for meta- and para-methyl red-doped nematics. Because of an elastic reorientation of the easy axis in the presence of the magnetic field, we could not determine the extrapolation length of the ortho-methyl red-doped nematic. Our results confirm that photoinduced reorientation is facilitated by desorption of all dyes from the polymer surface. While there is little evidence of weak photoinduced adsorption of meta- and para-methyl red to the surface during photoexcitation, there is strong evidence of photoinduced adsorption of ortho-methyl red, which is long lasting.
Journal
Physical Review E
Department
Physics
Citation
Statman, David, et al. 2015. "Comparison of photoinduced reorientation of ortho-, meta-, and para-methyl red-doped nematic liquid crystals on rubbed polyimide." Physical Review E 92, no. 2: 022503.
Publisher
American Physical Society
Version of Article
Published article
DOI
10.1103/PhysRevE.92.022503
ISSN
1539-3755
1550-2376
Rights
Statman, David, et al. 2015. "Comparison of photoinduced reorientation of ortho-, meta-, and para-methyl red-doped nematic liquid crystals on rubbed polyimide." Physical Review E 92, no. 2: 022503. ©2015 American Physical Society
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