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Chiral fluid membranes with orientational order and multiple edges.
Lijie Ding1, Robert A Pelcovits1,2, Thomas R Powers1,2,3,4
1Department of Physics, Brown University, Providence, RI 02912, USA. Lijie_Ding@alumni.brown.edu.
Soft Matter
|October 26, 2023
Summary
Monte Carlo simulations reveal how chiral liquid crystal membranes change shape and internal order. Chirality drives transitions from disk-like to complex shapes, forming distinct liquid crystal phases and π walls.
Area of Science:
- Soft Matter Physics
- Liquid Crystal Physics
- Computational Physics
Background:
- Fluid membranes exhibit complex behaviors influenced by bending resistance, edge tension, and orientational order.
- Chiral interactions and coupling between orientational order and membrane curvature can lead to exotic phases and morphologies.
- Understanding these phenomena is crucial for fields ranging from cell biology to materials science.
Purpose of the Study:
- To investigate the shape transitions and emergent liquid crystalline phases of fluid membranes with orientational order and multiple edges.
- To explore the effects of chirality and external forces on membrane morphology and director ordering.
- To develop a continuum model explaining the observed behaviors.
Main Methods:
- Monte Carlo simulations were performed on fluid membranes with defined physical properties (bending resistance, edge tension, tilt coupling, chiral interaction).
- Simulations were conducted both in the absence and presence of external stretching forces.
- A continuum model of the director field was constructed to interpret simulation results.
Main Results:
- In the absence of external forces, membranes transitioned from disk-like (low chirality, smectic-A phase) to catenoid or trinoid shapes (high chirality) with cholesteric ordering and π walls.
- Under stretching, membranes maintained cylindrical shapes but exhibited new liquid crystalline phases (smectic-A, nematic, cholesteric) depending on tilt coupling and chirality.
- The simulated π walls transitioned from tilt walls to twist walls as chirality increased.
Conclusions:
- Chirality is a key factor driving significant shape changes and the formation of complex director ordering in fluid membranes.
- External forces can stabilize different liquid crystalline phases, demonstrating the interplay between mechanical stress and internal order.
- The developed continuum model provides a theoretical framework for understanding the simulated membrane behaviors.
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