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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Phase diagrams of semisoft nematic elastomers
1Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, USA. fangfu@lci.kent.edu
The Journal of Physical Chemistry. B
|March 20, 2009
Summary
Nematic elastomers exhibit a unique semisoft elastic response, characterized by a stress-strain plateau. This behavior is linked to a specific broken symmetry phase and is a nonlinear phenomenon.
Area of Science:
- Materials Science
- Polymer Physics
- Soft Matter Physics
Background:
- Nematic elastomers display unique mechanical properties due to their anisotropic structure.
- A key characteristic is the 'semisoft' elastic response, featuring a stress plateau in stress-strain curves.
- Understanding the underlying phases and conditions for this response is crucial.
Purpose of the Study:
- To determine the phase diagram governing the semisoft elastic response in nematic elastomers.
- To investigate the connection between semisoft behavior and specific symmetry-broken phases.
- To explore the persistence of this phenomenon in different regimes and models.
Main Methods:
- Calculation of the global phase diagram for a minimal nematic elastomer model.
- Analysis of a nematic in crossed electric and magnetic fields as an equivalent system.
- Consideration of generalizations, including the neo-classical model by Warner, Bladon, and Terentjev.
Main Results:
- Semisoft elastic response is fundamentally linked to a broken symmetry biaxial phase.
- This behavior persists significantly into the supercritical regime.
- Similar results were observed in generalized models, including the neo-classical model.
- The semisoft response is a nonlinear phenomenon, not observable at zero external stress.
Conclusions:
- The semisoft elastic response in nematic elastomers is a nonlinear phenomenon tied to specific biaxial phases.
- Experimental conditions at zero external stress do not reveal information about this unique mechanical response.
- The findings provide a comprehensive phase diagram and highlight the importance of nonlinear analysis.
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