Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 3

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Enhancement of Nematic Order of Liquid Crystals in Thin Cells

100%
Aswini P., Govind A.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 3
625-627
EN
Experimental observations show that the nematic order parameter is significantly enhanced as the thickness of the cell is reduced. Calculations of earlier theories do not agree well with the experimental data. We propose a simple extension of Maier-Saupe theory to account for the enhancement. A molecule near the surface is assumed to feel the mean field potential (the Maier-Saupe type) and also the surface induced potential. This is included in the Maier-Saupe theory. Our calculations are in better agreement with the experimental data.
2
Content available remote

Theoretical Study of Nematic to Isotropic Transition in Porous Media

100%
Govind A., Banerjee K.
Acta Physica Polonica A
|
2016
|
vol. 130
|
issue 3
748-750
EN
Experimental observations show that the N-I transition temperature (T_{NI}) for liquid crystals embedded in solid porous materials is lower compared to that of the bulk liquid crystals and T_{NI} is reduced linearly with the inverse pore diameter. To explain this, various theoretical studies have been proposed. We propose to use the mean field approach. We modify the Maier-Saupe mean field theory to include the disordering effects of porosity as a disordering surface potential. A molecule near the surface is assumed to feel the mean field potential (the Maier-Saupe type) and also the surface induced potential. We calculate the values of the nematic order parameter and hence find the T_{NI} for different pore diameters. The weighted average of the order parameter is calculated considering the cylindrical symmetry of the pores. Our calculations on the variation of T_{NI} with pore diameter agree with experimental data. Also, the calculated values of specific heat peak decrease with decrease in pore radius, in agreement with experimental trends.
3
Content available remote

Theoretical Study of the Effect of Light on Nematic to Isotropic Phase Transition

81%
Suresha B., Radhakrishna M., Govind A.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 3
462-467
EN
Optical response of liquid crystals is very important from the point of view of applications of liquid crystals in display and data storage devices. Experiments have shown that UV rays incident on nematic liquid crystals doped with photoactive azo compounds lower the nematic isotropic transition temperature (T_{NI}). This is attributed to the transformation of photoactive trans isomer to cis isomer due to UV rays. We have earlier developed a mean field model involving molecular explanation for two lengths in which the mutual orientation of near neighbor molecules changes from an antiparallel to a parallel configuration as the temperature lowered. In this paper, this model is extended to include the length change from trans to cis isomer. The calculated values of change in T_{NI} qualitatively agree with experimental trends.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.