Near axisymmetric partial wetting using interface-localized liquid dielectrophoresis

Brabcova, Z, McHale, G, Wells, GG, Brown, CV ORCID: https://orcid.org/0000-0002-1559-3238, Newton, MI ORCID: https://orcid.org/0000-0003-4231-1002 and Edwards, AMJ ORCID: https://orcid.org/0000-0003-3338-1287, 2016. Near axisymmetric partial wetting using interface-localized liquid dielectrophoresis. Langmuir, 32 (42), pp. 10844-10850. ISSN 0743-7463

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Abstract

The wetting of solid surfaces can be modified by altering the surface free energy balance between the solid, liquid, and vapour phases. Liquid dielectrophoresis (L-DEP) can produce wetting on normally non-wetting surfaces, without modification of the surface topography or chemistry. L-DEP is a bulk force acting on the dipoles of a dielectric liquid and is not normally considered to be a localized effect acting at the interface between the liquid and a solid or other fluid. However, if this force is induced by a non-uniform electric field across a solid -liquid interface, it can be used to enhance and control the wetting of a dielectric liquid. Recently, it was reported theoretically and experimentally that this approach can cause a droplet of oil to spread along parallel interdigitated electrodes thus forming a stripe of liquid. Here we show that by using spiral shaped electrodes actuated with four 90º successive phase shifted signals, a near axisymmetric spreading of droplets can be achieved. Experimental observations show that the induced wetting can achieve film formation, an effect not possible with electrowetting. We show that the spreading is reversible thus enabling a wide range of partial wetting droplet states to be achieved in a controllable manner. Furthermore, we find that the cosine of the contact angle has a quadratic dependence on applied voltage during spreading and deduce a scaling law for the dependence of the strength of the effect on the electrode size.

Item Type:	Journal article
Publication Title:	Langmuir
Creators:	Brabcova, Z., McHale, G., Wells, G.G., Brown, C.V., Newton, M.I. and Edwards, A.M.J.
Publisher:	American Chemical Society
Date:	October 2016
Volume:	32
Number:	42
ISSN:	0743-7463
Identifiers:	Number Type 10.1021/acs.langmuir.6b03010 DOI
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	26 Oct 2016 13:12
Last Modified:	15 May 2019 13:24
URI:	https://irep.ntu.ac.uk/id/eprint/28948

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