Electric field induced reversible spreading of droplets into films on lubricant impregnated surfaces

Brabcova, Z, McHale, G, Wells, GG, Brown, CV ORCID: https://orcid.org/0000-0002-1559-3238 and Newton, MI ORCID: https://orcid.org/0000-0003-4231-1002, 2017. Electric field induced reversible spreading of droplets into films on lubricant impregnated surfaces. Applied Physics Letters, 110 (12), p. 121603. ISSN 0003-6951

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Abstract

Electric fields can be used to force a droplet to wet a solid surface using an applied voltage. However, significant hysteresis usually occurs associated with pinning forces at the contact line. Here, we report the forced spreading and subsequent retraction of droplets into liquid films in air on lubricant impregnated surfaces (also known as slippery liquid infused porous surfaces) where the contact line is completely mobile. We first confirm that we achieve a complete removal of hysteresis for the electrowetting of droplets above the saturation voltage. We then show that contact angle hysteresis can be reduced to less than 4° whilst retaining the ability to fully spread a droplet into a liquid film using an interface localized from liquid dielectrophoresis (dielectrowetting). In both cases, we find that the cosine of the contact angle has a quadratic dependence on applied voltage, consistent with previous theoretical expectations. Thus, our work demonstrates that fully reversible spreading encompassing a wide range of partial wetting droplet states and a film state can be achieved in air in a controllable manner with very low levels of hysteresis.

Item Type:	Journal article
Publication Title:	Applied Physics Letters
Creators:	Brabcova, Z., McHale, G., Wells, G.G., Brown, C.V. and Newton, M.I.
Publisher:	AIP Publishing
Date:	23 March 2017
Volume:	110
Number:	12
ISSN:	0003-6951
Identifiers:	Number Type 10.1063/1.4978859 DOI
Record created by:	Jonathan Gallacher
Date Added:	27 Mar 2017 09:00
Last Modified:	09 Jun 2017 14:13
URI:	https://irep.ntu.ac.uk/id/eprint/30445

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