All Publications

  • The spatial structure of electrostatically forced Faraday waves JOURNAL OF FLUID MECHANICS Dehe, S., Hartmann, M., Bandopadhyay, A., Hardt, S. 2022; 939
  • Deformation modes of an oil-water interface under a local electric field: From Taylor cones to surface dimples PHYSICAL REVIEW FLUIDS Dehe, S., Hardt, S. 2021; 6 (12)
  • Hydrodynamic dispersion in Hele-Shaw flows with inhomogeneous wall boundary conditions JOURNAL OF FLUID MECHANICS Dehe, S., Rehm, I., Hardt, S. 2021; 925
  • Intermediate States of Wetting on Hierarchical Superhydrophobic Surfaces LANGMUIR Rofman, B., Dehe, S., Frumkin, V., Hardt, S., Bercovici, M. 2020; 36 (20): 5517-5523


    Wetting transition on superhydrophobic surfaces is commonly described as an abrupt jump between two stable states-either from Cassie to Wenzel for nonhierarchical surfaces or from Cassie to nano-Cassie on hierarchical surfaces. We here experimentally study the electrowetting of hierarchical superhydrophobic surfaces composed of multiple length scales by imaging the light reflections from the gas-liquid interface. We present the existence of a continuous set of intermediate states of wetting through which the gas-liquid interface transitions under a continuously increasing external forcing. This transition is partially reversible and is limited only by localized Cassie to Wenzel transitions at nanodefects in the structure. In addition, we show that even a surface containing many localized wetted regions can still exhibit extremely low contact angle hysteresis, thus remaining useful for many heat transfer and self-cleaning applications. Expanding the classical definition of the Cassie state in the context of hierarchical surfaces, from a single state to a continuum of metastable states ranging from the centimeter to the nanometer scale, is important for a better description of the slip properties of superhydrophobic surfaces and provides new considerations for their effective design.

    View details for DOI 10.1021/acs.langmuir.0c00499

    View details for Web of Science ID 000537681700005

    View details for PubMedID 32337996

  • Electro-osmotic flow enhancement over superhydrophobic surfaces PHYSICAL REVIEW FLUIDS Dehe, S., Rofman, B., Bercovici, M., Hardt, S. 2020; 5 (5)