With six surfaces prepared for different surface division patterns

steam condensation heat transfer characteristics on dropwise and film coexisting surfaces were investigated experimentally under atmospheric pressure. Dropwise condensation was promoted with ultrathin polytetrafluoroethylene (FIFE) film

which was prepared by the dynamic ion-beam mixed implantation (DIMI) method. It was found that the condensation phenomena at the interconnecting section between dropwise and film condensation parts were quite different for the different relative position of dropwise and film condensation parts. Experimental results revealed that condensation heat transfer characteristics were greatly influenced by the surface division pattern and the relative area ratio of dropwise and film condensation parts. The enhancement mechanism of condensation heat transfer was discussed accordingly.