Effect of condensation phenomena on the nanostructured hydrophobic polymer film during heat transfer

Polymer has drawn attention to use as heat exchanger due to their special characteristics such as flexibility, low weight, corrosion, and bio-fouling resistance, as well as their ease of manufacturing. However, since its thermal conductivity is low, it requires a way to increase its heat transfer rate. We investigated the effect of modifying the surface wettability of polymer films on the heat transfer rate during the condensation process, both theoretically and experimentally. Here, we used four different types of polymer films, which have different thermal conductivity and controlled wettability properties. We designed a thermal resistance model to compare the heat transfer rate of each sample and analyzed which resistance is dominant in the thermal resistance. We found that the convective thermal resistance dominantly affects the heat transfer rate and treated polymers showed over 200% higher total heat transfer than bare polymer.