Drop dynamics on chemically patterned surfacesH. Kusumaatmaja1, J. Léopoldès2, A. Dupuis1 and J. M. Yeomans1
1 The Rudolf Peierls Centre for Theoretical Physics, Oxford University 1 Keble Road, Oxford OX1 3NP, UK
2 Department of Materials, Oxford University - Parks Road, Oxford OX1 3PH, UK
received 17 October 2005; accepted in final form 5 January 2006
published online 18 January 2006
We compare numerical and experimental results exploring the behaviour of liquid drops moving across a surface patterned with hydrophobic and hydrophilic stripes. A lattice Boltzmann algorithm is used to solve the hydrodynamic equations of motion of the drops allowing us to investigate their behaviour as the stripe widths and the wettability contrast are altered. We explain how the motion of the drop is determined by the interplay between the driving force and the variation in surface force as the drop moves between regions of different contact angle and we find that the shape of the drops can undergo large periodic deviations from spherical. When compared, the numerical results agree well with experiments on micron-scale drops moving across substrates patterned by microcontact printing.
68.08.Bc - Wetting.
47.61.Jd - Multiphase flows.
47.61.-k - Micro- and nano- scale flow phenomena.
© EDP Sciences 2006