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Re-entrant phase behaviour of network fluids: a patchy particle model with temperature-dependent valence.
J Russo1, J M Tavares, P I C Teixeira
1Dipartimento di Fisica and CNR-ISC, Università di Roma La Sapienza, Piazzale A. Moro 2, I-00185 Rome, Italy. john.russo.mcdougall@gmail.com
The Journal of Chemical Physics
|July 27, 2011
Summary
This study explores self-assembling patchy particles. Increasing Y-junction energy cost alters phase behavior, reducing liquid-vapor coexistence and potentially eliminating condensation, revealing a novel topological phase transition.
Area of Science:
- Colloid and materials science
- Statistical mechanics
- Computational chemistry
Background:
- Patchy particles are model systems for studying self-assembly.
- Understanding phase behavior is crucial for designing self-assembling materials.
- Topological phase transitions are rare and challenging to observe in physical models.
Purpose of the Study:
- To investigate the phase behavior of a model with particles forming Y-junctions.
- To explore the impact of Y-junction formation energy on self-assembly and phase transitions.
- To observe and characterize a predicted topological phase transition.
Main Methods:
- Particle-based simulations were employed to model self-assembly.
- Theoretical analysis was used to understand the observed phase behavior.
- The energy cost of Y-junctions (ε(j)) was systematically varied.
Main Results:
- Increased Y-junction energy cost reduces liquid-vapor coexistence and creates a 'pinched' phase diagram.
- A topological phase transition between short-chain and Y-junction-rich fluids was observed.
- Condensation was suppressed above a threshold energy cost due to entropic limitations.
Conclusions:
- The model successfully demonstrates a topological phase transition driven by Y-junction formation.
- Phase diagram properties are linked to a temperature-dependent effective valence of particles.
- This work provides insights into controlling self-assembly through particle design and interaction energies.
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