Unlocking the full potential of jumping condensation on microstructured surfaces

TL;DR

This study demonstrates that engineered microscale conical arrays can enable droplet jumping during condensation, with a critical spacing threshold that determines whether droplets are rapidly removed or not, informing design principles for efficient condensation surfaces.

Contribution

The paper reveals a spacing-dependent transition in jumping condensation on microscale conical arrays, establishing design principles for scalable, robust surfaces for enhanced condensation management.

Findings

Critical spacing threshold for droplet jumping identified

Dense arrays promote full Cassie droplets and clean departure

Wider spacing leads to partial Cassie droplets and nucleation

Abstract

Water condensation on superhydrophobic surfaces can generate spontaneous droplet jumping, enabling rapid condensate removal and improved thermal and mass transfer. Although this effect has been extensively demonstrated on densely packed nanostructures, the capability of microscale textures to support jumping condensation remains poorly understood. Here, we show that engineered microscale conical arrays can achieve efficient microdroplet jumping and reveal a previously unreported spacing-dependent critical transition between jumping and non-jumping regimes. In the jumping regime, by varying only the cone pitch, we identify a geometric threshold below which sub-10 micron droplets are rapidly removed, and above which jumping is suppressed, resulting in slower dynamics and larger departing droplets. In situ optical and environmental scanning electron microscopies reveal the mechanistic origin of this transition: dense arrays favour full Cassie droplets, which depart cleanly, while wider spacing favours partial Cassie droplets that retain a localized wet region initiating new nucleation. From these results, we construct a geometry-wetting design map linking microstructure spacing, droplet morphology, and nucleation density. These findings establish design principles for scalable, mechanically robust microstructured surfaces capable of high-performance condensation management for anti-fogging, water harvesting, and heat-transfer applications.