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The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids
Published on: September 30, 2014
New electric-field-driven mesoscale phase transitions in polarized suspensions
Anil Kumar1, Boris Khusid, Zhiyong Qiu
1The Levich Institute, The City College of New York, 140th Street & Convent Avenue, New York, New York 10031, USA.
Physical Review Letters
|December 31, 2005
Summary
We discovered a new electric field-driven phase transition in suspensions caused by dipolar interactions. This transition rearranges particle columns into a cellular pattern, with domain size dependent on electrode spacing, not particle size.
Area of Science:
- Colloid and Interface Science
- Soft Matter Physics
- Materials Science
Background:
- Electric fields induce phase transitions in suspensions, often forming chain-like structures.
- Dipolar interactions are a key force in colloidal systems under electric fields.
- Competing forces can obscure fundamental transition mechanisms.
Purpose of the Study:
- To identify and characterize a novel bulk phase transition in suspensions driven solely by dipolar interactions.
- To investigate the transition mechanism under a uniform AC electric field with suppressed competing forces.
- To understand the relationship between the resulting cellular pattern and experimental parameters.
Main Methods:
- Utilizing a uniform AC electric field to drive transitions in a colloidal suspension.
- Suppressing competing forces to isolate the effects of dipolar interactions.
- Observing and analyzing the suspension's structural rearrangement from columns to a cellular pattern.
- Measuring the characteristic domain size of the cellular pattern and its dependence on interelectrode spacing and particle size.
Main Results:
- A new class of electric field-driven bulk phase transition, solely due to dipolar interactions, was discovered.
- This transition occurs after initial chain-column formation, leading to a cellular pattern.
- The cellular pattern features particle-free domains enclosed by particle-rich walls.
- The domain size scales linearly with interelectrode spacing and is independent of particle size.
Conclusions:
- Dipolar interactions alone can drive a distinct bulk phase transition in suspensions under AC electric fields.
- The observed cellular pattern formation provides a new route for structuring colloidal suspensions.
- The linear scaling of domain size with interelectrode spacing offers potential for controlled pattern generation.
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