Nature-inspired
magnetically responsive intelligent topography
surfaces have attracted considerable attention owing to their controllable
droplet manipulation abilities. However, it is still challenging for
magnetically responsive surfaces to realize three-dimensional (3D)
droplet/multidroplet transport in both horizontal and vertical directions.
Additionally, the droplet horizontal propulsion speed needs to be
improved. In this work, a 3D droplet/multidroplet transport strategy
based on magnetically responsive microplates array (MMA) actuated
by a spatially varying and periodic magnetic field is proposed. The
modified superhydrophobic surface can transport droplets rapidly both
in horizontal and vertical directions, and it can even realize against-gravity
upslope propulsion. The rapid horizontal droplet propulsion (∼58.6
mm/s) is ascribed to the abrupt inversion of the modified surface
induced by the specific magnetic field. Furthermore, the nonmagnetically
responsive microplates (NMMs)/MMA composite surface is constructed
to realize 3D multidroplet manipulation. The implementations of MMA
in manipulation of continuous fluids and liquid metal are further
demonstrated, providing a valuable platform for microfluidic applications.