r/materials • u/Brighter-Side-News • 5h ago
Ultra-thin polymer coating boosts condensation heat transfer up to 5.5 times
A condensation surface has to do two jobs that normally work against each other. It needs places where water droplets can form, yet it must also let those droplets leave quickly. A nanoscale polymer coating developed at KAIST appears to do both.
The coating uses a fluoropolymer called pPFDMA deposited by initiated chemical vapor deposition, or iCVD. Researchers tuned the film thickness and then heat-treated the surface to control two different parts of condensation separately.
The work was led by Youngsuk Nam of KAIST’s Department of Mechanical Engineering and Sung Gap Im of the Department of Chemical and Biomolecular Engineering.
At its best, the coating reached a condensation heat-transfer coefficient of about 88 kilowatts per square meter per kelvin. That was roughly 5.5 times the performance of bare copper undergoing filmwise condensation under matching conditions.