Unraveling Condensation Frosting through Controlled Experiments and Complex Networks

Condensation frosting is ubiquitously observed in cold countries and various industrial applications, ranging from refrigeration to aerospace systems. In recent years, there has been growing interest in using superhydrophobic and other nanoengineered coatings to delay frost formation and minimize ice adhesion. In this study, we systematically investigate the condensation frosting behavior on a variety of nanoengineered surfaces, including hydrophilic (HPL), superhydrophilic (SHPL), superhydrophobic (SHPB), and lubricant-infused surfaces (LIS), under varying humidity differentials (Δω = 3–6.1 g/kg of dry air). We identify distinct regimes during the frosting process by monitoring the evolution of the time-resolved surface temperature and heat flux. The results reveal surface-dependent frost propagation mechanisms, and the extent of frost coverage over 7200 s is quantified. Frost propagation exhibits a strong dependence on wettability: SHPL and HPL surfaces achieve >90% area coverage within ∼3600 s, whereas SHPB remains below ∼85% even after ∼7200 s. The corresponding area averaged propagation velocities follow SHPL (∼1.2 mm2/s) > HPL (∼1.0 mm2/s) > LIS (∼0.5 mm2/s) > SHPB (∼0.25 mm2/s), reflecting the effect of wettability, nucleation density, and droplet mobility. Furthermore, a novel image-based complex network framework is introduced to quantify the evolving mesoscale structure and phase transitions during condensation and frost formation. These in-depth insights into condensation frosting and the detection of its onset and propagation will improve the design and control of advanced antifrosting surface technologies for practical applications.