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Updated: Jul 20, 2025
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Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions
Published on: April 19, 2018
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Entropy of different phases formed by soft rods
Jayeeta Chattopadhyay1,2, Shiang-Tai Lin3, Prabal K Maiti1
1Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
The Journal of Chemical Physics
|August 3, 2023
Summary
The two-phase thermodynamic model (2PT) accurately calculates entropy in liquid crystal (LC) phases for soft repulsive spherocylinders. Entropy values are similar across different LC phases for a given packing fraction.
Area of Science:
- Statistical Physics
- Soft Matter Physics
- Thermodynamics
Background:
- Calculating entropy in liquid and liquid crystal (LC) phases presents a significant challenge in statistical physics.
- Existing models often struggle with shape-anisotropic systems.
Purpose of the Study:
- Extend the two-phase thermodynamic model (2PT) to soft repulsive spherocylinders (SRSs).
- Determine absolute entropy values for various LC phases and aspect ratios.
- Investigate the contributions of translational and rotational degrees of freedom to entropy.
Main Methods:
- Applied the 2PT model to shape-anisotropic SRSs with aspect ratios L/D = 2-5.
- Calculated the density of states and decomposed it into translational and rotational components.
- Utilized a fluidicity factor to partition modes into diffusive (gas-like) and non-diffusive (solid-like) categories.
Main Results:
- 2PT model results align with ideal rigid rotor calculations in the dilute limit.
- Total entropy magnitude is consistent across different LC phases for a fixed packing fraction.
- Computed excess entropy for L/D=5, showing excellent agreement with standard molecular dynamics (MD) and Monte Carlo methods.
Conclusions:
- The 2PT model provides accurate entropy calculations for anisotropic soft matter systems.
- Fluidicity factors derived from translational and rotational motion can predict LC phase boundaries.
- Entropy is largely independent of specific LC phase for a given packing fraction in these systems.
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