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Instabilities in nematic elastomers in external electric and magnetic fields
1Theoretische Physik III, Universität Bayreuth, Bayreuth, Germany. andreas.menzel@uni-bayreuth.de
The European Physical Journal. E, Soft Matter
|May 8, 2008
Summary
This study investigates nematic liquid crystal elastomers under electric or magnetic fields. Researchers propose methods to determine material parameters like twist coefficient K(2) and D(1), D(2) from experimental observations.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Polymer Science
Background:
- Nematic side-chain liquid crystal elastomers exhibit unique macroscopic behaviors.
- Understanding their response to external fields is crucial for material applications.
- The Frederiks transition in low molecular weight liquid crystals provides a basis for comparison.
Purpose of the Study:
- To investigate the macroscopic behavior of nematic side-chain liquid crystal elastomers under electric or magnetic fields.
- To analyze the instabilities occurring in bend and twist geometries.
- To propose experimental methods for determining key material parameters.
Main Methods:
- Utilizing a continuum model to describe the macroscopic behavior.
- Investigating both bend and twist geometries.
- Analyzing the onset and nature of instabilities.
Main Results:
- For bend geometry, both laterally homogeneous and 2D undulatory instabilities were identified.
- For twist geometry, three instabilities were found, with two exhibiting 2D undulations.
- A method is proposed to determine twist coefficient K(2) and material parameters D(1) and D(2).
Conclusions:
- The study provides insights into the field-induced instabilities of nematic liquid crystal elastomers.
- Experimental determination of material parameters, particularly D(1) using twist experiments, is facilitated.
- The findings contribute to the understanding and characterization of these advanced materials.
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