We present a method to move and control drops of water on superhydrophobic surfaces using magnetic fields. Small water drops (volume of 5-35 μl) that contain fractions of paramagnetic particles as low as 0.1% in weight can be moved at relatively high speed (7 cm/s) by displacing a permanent magnet placed below the surface. Coalescence of two drops has been demonstrated by moving a drop that contains paramagnetic particles towards an aqueous drop that was previously pinned to a surface defect. This approach to microfluidics has the advantages of faster and more flexible control over drop movement.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)