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Impact of water drops onto the junction of a hydrophobic texture and a hydrophilic smooth surface

Vaikuntanathan, V and Kannan, R and Sivakumar, D (2010) Impact of water drops onto the junction of a hydrophobic texture and a hydrophilic smooth surface. In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 369 (1-3). pp. 65-74.

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Official URL: http://dx.doi.org/10.1016/j.colsurfa.2010.07.034


Wettability gradient surfaces play a significant role in control and manipulation of liquid drops. The present work deals with the analysis of water drops impacting onto the junction line between hydrophobic texture and hydrophilic smooth portions of a dual-textured substrate made using stainless steel material. The hydrophobic textured portion of the substrate comprised of unidirectional parallel groove-like and pillar-like structures of uniform dimensions. A high-speed video camera recorded the spreading and receding dynamics of impacting drops. The drop impact dynamics during the early inertia driven impact regime remains unaffected by the dual-texture feature of the substrate. A larger retraction speed of drop liquid observed on the hydrophobic portion of the substrate during the impact of low velocity drops makes the drop liquid on the higher wettability portion to advance further (secondary drop spreading). The net horizontal drop velocity towards the hydrophilic portion of the dual-textured substrate decreases with increasing drop impact velocity. The available experimental results suggest that the movement of bulk drop liquid away from the impact point during drop impact on the dual-textured substrate is larger for the impact of low inertia drops. (C) 2010 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Publication: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Publisher: Elsevier Science B.V.
Additional Information: Copyright of this article belongs to Elsevier Science B.V.
Keywords: Wettability gradient surface; Drop impact; Hydrophobic surface; Textured surface
Department/Centre: Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited: 08 Nov 2010 09:55
Last Modified: 08 Nov 2010 09:55
URI: http://eprints.iisc.ac.in/id/eprint/33675

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