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Reorientation effect and electrical current in a weakly anchored nematic cell.
R Teixeira de Souza1, M M A de Jesus, J C Dias
1Departamento de Física, Universidade Estadual de Maringá Avenida Colombo, 5790-87020-900 Maringá, Paraná, Brazil.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 13, 2009
Summary
This study analyzes electric current in nematic cells under electric fields. Researchers found a way to estimate anchoring energy by measuring current, offering a new experimental method for characterizing liquid crystals.
Area of Science:
- Physics
- Materials Science
- Electrical Engineering
Background:
- Nematic liquid crystals exhibit unique electrical properties influenced by molecular reorientation under electric fields.
- Understanding the relationship between applied voltage and current is crucial for device applications.
Purpose of the Study:
- To analytically determine the dependence of electrical current on applied voltage in a nematic cell.
- To establish a method for experimentally estimating anchoring energy in nematic liquid crystals.
Main Methods:
- Modeling the nematic cell as parallel resistance R(t) and capacitance C(t).
- Determining the nematic director profile in the quasistatic regime.
- Analyzing current behavior under varying electric fields and anchoring conditions.
Main Results:
- The current exhibits a peak at the threshold voltage for the Fréedericksz transition, regardless of anchoring strength.
- For large voltages and long times, simple analytical expressions connect current to extrapolation length.
- The study demonstrates a direct link between measurable current and anchoring energy.
Conclusions:
- The electrical current in nematic cells provides a viable pathway for experimentally determining anchoring energy.
- This method offers a new tool for characterizing liquid crystal materials and their surface interactions.
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