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Updated: Aug 6, 2025
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
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Two-temperature activity induces liquid-crystal phases inaccessible in equilibrium
Jayeeta Chattopadhyay1, Sriram Ramaswamy1, Chandan Dasgupta1
1Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Physical Review. E
|March 18, 2023
Summary
Active soft spherocylinders self-organize into novel liquid-crystalline phases. This molecular dynamics study reveals nematic and smectic phases at lower aspect ratios than predicted by equilibrium theories.
Area of Science:
- Soft matter physics
- Liquid crystals
- Non-equilibrium statistical mechanics
Background:
- Equilibrium hard-rod fluids exhibit isotropic-nematic transitions above an aspect ratio of 3.70, as per Onsager's theory.
- Anisotropic soft-particle systems often use effective hard-rod descriptions.
- Understanding phase transitions in active matter systems is crucial for predicting self-organization.
Purpose of the Study:
- To investigate the fate of the Onsager criterion in an active system of soft repulsive spherocylinders.
- To explore phase behavior and self-organization in a non-equilibrium system with differential heating.
- To identify novel liquid-crystalline phases not observed in equilibrium.
Main Methods:
- Molecular dynamics simulations were employed.
- A system of soft repulsive spherocylinders was studied.
- Activity was introduced by coupling half the particles to a higher temperature heat bath.
Main Results:
- The active system undergoes phase separation and self-organizes into various liquid-crystalline phases.
- A nematic phase was observed for a rod aspect ratio (L/D) of 3.
- A smectic phase was observed for L/D=2 above a critical activity level.
Conclusions:
- The Onsager criterion for isotropic-nematic transitions is altered in active soft-rod systems.
- Non-equilibrium conditions, specifically activity, can induce liquid-crystalline ordering at lower aspect ratios.
- The study demonstrates the potential for self-organization into novel phases in active anisotropic fluids.
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