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Equilibrium "wetting" of surfaces by membrane-covered vesicles
1Pathology and Physics, University of British Columbia, Vancouver.
Advances in Colloid and Interface Science
|April 6, 1992
Summary
Thin-membrane capsules
Area of Science:
- Colloid and Surface Science
- Soft Matter Physics
- Materials Science
Background:
- Wetting of surfaces by thin-membrane capsules is crucial for the coagulation of surfactant membrane vesicles and microemulsions.
- Unlike macroscopic wetting by liquid droplets, membrane wetting involves membrane tension and variable effective contact angles.
Purpose of the Study:
- To investigate the determinants of surface wetting by membrane capsules.
- To understand the transition from maximal substrate contact to partial contact with membrane lamination.
- To explore the influence of thermal fluctuations on wetting behavior.
Main Methods:
- Theoretical analysis of membrane mechanics and adhesion energies.
- Modeling of geometric constraints (area and volume) on capsule shape and contact.
- Investigation of the role of membrane-membrane and membrane-substrate adhesion.
Main Results:
- Geometric restrictions (area and volume) primarily determine wetting extent for strong adhesion.
- A transition occurs when membrane-membrane attraction competes with membrane-substrate attraction, leading to partial contact and lamination.
- Effective contact angle depends on the ratio of self-adhesion to substrate adhesion energies.
- Area excess over a sphere dictates the transition condition.
- Restriction of thermal fluctuations leads to unconventional elastic responses and a crossover in wetting regimes.
Conclusions:
- Surface wetting by membrane capsules is governed by a complex interplay of geometric constraints, adhesion energies, and thermal fluctuations.
- The system exhibits a transition from strong to weak wetting regimes based on these factors.
- Understanding these principles is key for controlling microemulsion and vesicle behavior.
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