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Hydrodynamic effects on the liquid-hexatic transition of active colloids
G Negro1, C B Caporusso2, P Digregorio3
1Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, 70126, Italy.
The European Physical Journal. E, Soft Matter
|September 13, 2022
Summary
Hydrodynamics influence the liquid-hexatic transition in active colloids. Increased particle mass enhances ordering for active Brownian particles (ABP), while active hydrodynamic particles (AHP) show disordered behavior and coherent motion clusters.
Area of Science:
- Soft matter physics
- Statistical mechanics
- Colloidal systems
Background:
- Active colloids exhibit complex phase behaviors.
- The liquid-hexatic transition is a key phenomenon in two-dimensional systems.
- Motility-induced phase separation (MIPS) is a common ordering mechanism in active matter.
Purpose of the Study:
- To numerically investigate the role of hydrodynamics in the liquid-hexatic transition of active colloids.
- To understand how particle mass and self-propulsion affect ordering at intermediate activity.
- To compare the behavior of active Brownian particles (ABP) and active hydrodynamic particles (AHP).
Main Methods:
- Numerical simulations of active Brownian particles (ABP) and active hydrodynamic particles (AHP).
- Analysis of phase transitions at varying particle densities, mass, and activity levels.
- Examination of ordering and collective motion within the systems.
Main Results:
- For ABP, increased particle mass enhances ordering, while self-propulsion decreases it at intermediate activity.
- AHP exhibit the liquid-hexatic transition at higher densities compared to ABP, indicating a net disordering effect from hydrodynamics.
- AHP display self-sustained organized motion and coherent particle clusters near the hexatic-liquid transition.
Conclusions:
- Hydrodynamics play a significant role in modulating the liquid-hexatic transition in active colloids.
- The interplay between particle mass, self-propulsion, and hydrodynamics dictates system ordering.
- Active hydrodynamic interactions can lead to emergent collective behaviors like coherent cluster motion.
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