Tailoring surface structures for enhanced single‐droplet jumping condensation

Abstract Efficient condensate removal is critical for sustaining high heat‐transfer rates. While coalescence‐induced droplet jumping on superhydrophobic surfaces has been widely studied as a passive mode of water removal, its efficiency is limited by an intrinsically low energy conversion efficiency (<6%). Single‐droplet jumping, driven by internal Laplace pressure difference, enhances energy conversion efficiency and thus serves as a promising alternative. Here, superhydrophobic SU8 micropillar arrays with controlled geometries (dimensions in the range of 5‒20 ) are developed and used to conduct evaluations of design parameters that enhance number of single‐droplet jumping during condensation. Using environmental scanning electron microscopy, nucleation, growth, and jumping dynamics are investigated across pillars with effective aspect ratios, defined as measured pillar heights divided by edge spacings at tops of pillars; ranging from 1.0 to 3.4 and three geometries: square, triangular, and hexagonal. Our results reveal critical design criteria for enabling single‐droplet jumping during water vapor condensation: (i) sufficient confinement energy release; (ii) minimization of the nucleation‐to‐jump period; and (iii) maximizing number of jumping sites. This work demonstrates a passive method for fast and efficient transport and shedding of droplets having micrometer to millimeter length scales.