R. Tsekov, D. Borissov, S. I. Karakashev
A theory for wetting of structured solid surfaces is developed, based on a delta-comb periodic surface potential. It possesses two matching parameters: an effective line tension and a friction coefficient on the three-phase contact line at the surface. The theory is validated on the dynamics of spreading of liquid zinc drops on morphologically patterned hydrophilic iron surface by means of square patterns of hydrophobic aluminum oxide. It is found out that the effective line tension is negative and has essential contribution to the dynamics of spreading. Thus, the theoretical analysis shows that the presence of hydrophobic patterns situated on hydrophilic surface makes the latter even super-hydrophilic, i.e. no equilibrium contact angle on such surface exists making the droplet spread completely in form of thin liquid layer on the patterned surface.
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http://arxiv.org/abs/1212.3791
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