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Workshops

Computational methods for modelling multiply-charged droplets

July 6, 2016 to July 8, 2016
Location : CECAM-HQ-EPFL, Lausanne, Switzerland
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Charged materials in alternating electric field

Robert Holyst
University of Warsaw, Poland

Abstract

Charged materials are always electrically neutral and strong, long range Coulomb interactions are screened by ions. Electric field of low frequency moves these ions and separates plus and minus charges for a short period of time. These ions can shift boundaries between materials of different conductivity. The strongest effects are observed for such frequencies of the field that makes the ions travel a distance of the size of the Debye length in one period of the electric field. I will show a number of experiments performed on such systems. They are as follows: a freely suspended polar/ferroelectric liquid crystals, mixtures of polymers and liquid crystals undergoing phase separation, microfluidic system of water droplets immersed in oil and finally water between plates, at hundreds of nanometer separation, in the surface force apparatus.



References

1. T Szymborski et al. Ionic polarization of liquid-liquid interfaces; dynamic control of the rate of electro-coalescence Applied Physics Letters 99 (9), 094101 (2011).
2. T Szymborski et al. Dynamic charge separation in a liquid crystalline meniscus, Soft Matter 5 (12), 2352-2360 (2009).

3. N Ziębacz et al. Thousand‐Fold Acceleration of Phase Decomposition in Polymer/Liquid Crystal Blends ChemPhysChem 10 (15), 2620-2622, (2009).