Water vapor condensation on metallic surfaces is critical
to a
broad range of applications, ranging from power generation to the
chemical and pharmaceutical industries. Enhancing simultaneously the
heat transfer efficiency, scalability, and durability of a condenser
surface remains a persistent challenge. Coalescence-induced condensing
droplet jumping is a capillarity-driven mechanism of self-ejection
of microscopic condensate droplets from a surface. This mechanism
is highly desired due to the fact that it continuously frees up the
surface for new condensate to form directly on the surface, enhancing
heat transfer without requiring the presence of the gravitational
field. However, this condensate ejection mechanism typically requires
the fabrication of surface nanotextures coated by an ultrathin (<10
nm) conformal hydrophobic coating (hydrophobic self-assembled monolayers
such as silanes), which results in poor durability. Here, we present
a scalable approach for the fabrication of a hierarchically structured
superhydrophobic surface on aluminum substrates, which is able to
withstand adverse conditions characterized by condensation of superheated
steam shear flow at pressure and temperature up to ≈1.42 bar
and ≈111 °C, respectively, and velocities in the range
≈3–9 m/s. The synergetic function of micro- and nanotextures,
combined with a chemically grafted, robust ultrathin (≈4.0
nm) poly-1H,1H,2H,2H-perfluorodecyl acrylate (pPFDA) coating, which
is 1 order of magnitude thinner than the current state of the art,
allows the sustenance of long-term coalescence-induced condensate
jumping drop condensation for at least 72 h. This yields unprecedented,
up to an order of magnitude higher heat transfer coefficients compared
to filmwise condensation under the same conditions and significantly
outperforms the current state of the art in terms of both durability
and performance establishing a new milestone.