No abstract

Water repellency is most often generated by taking advantage of surface textures [1,2] and low surface energy coatings such as the one afforded by polymers possessing long perfluorinated side chains [3-

A majority of the work devoted to surface engineering for promoting dropwise condensation heat transfer has focused on steam. However, many industrial condensation processes such as HVAC, refrigeration, and organic Rankine cycles (ORCs) condense low-surface-tension fluids such as hydrocarbons and refrigerants. Here, we demonstrate dropwise condensation of these liquids using initiated chemical vapor deposition to graft low-energy nanofilms to a variety of heat exchanger materials, measure heat transfer coefficient improvement, and estimate overall cycle efficiency improvement for ORCs.

Clathrate hydrates are icelike solid substances that can form inside oil and gas pipelines and are responsible for flow blockages, sometimes leading to catastrophic failures. Minimizing hydrate formation and adhesion on pipeline surfaces can effectively address this problem. In this paper, we achieve the lowering of the adhesion of cyclopentane hydrates by promoting a cyclopentane barrier film between the hydrate and solid surface. The presence of this interfacial liquid film depends on the relative spreading of cyclopentane on the solid surface in the presence of water. We study the role of surface chemistry and surface texture on the spreading characteristics of such interfacial films and their impact on hydrate adhesion. The use of the spreading coefficients as design parameters could take us a step closer to the development of effective passive antihydrate surfaces.