Pfeiffer, Till ; Kappl, Michael ; Li, Shuai ; Butt, Hans-Jürgen ; Stephan, Peter ; Gambaryan-Roisman, Tatiana (2023)
Condensation of water on PDMS-coated copper surfaces.
17th International Heat Transfer Conference. Cape Town, South Africa (14.08.2023-18.08.2023)
doi: 10.1615/ihtc17.60-20
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Kurzbeschreibung (Abstract)

One of the approaches to achieve high condensation rates is modification of surfacewetting behavior to enable a dropwise condensation. In this work, condensation experiments of water on PDMS-coated copper surfaces is presented. First, the fabrication method of PDMS-coated copper substrates including turning, sanding, polishing, oxidation and polymer coating is introduced. The roughness of surfaces was characterized by 3D confocal microscopy, and wetting behaviour has been studied by goniometry. The roughness arithmetical mean height was 22nm. An advancing contact angle of 111°±1°, a receding contact angle of 109°±1° and a resulting contact angle hysteresis of 2° were measured. The condensation heat transfer has been studied on uncoated and on PDMS-coated surfaces in saturated water vapor atmosphere. The transferred heat as well as wall and vapor temperatures were recorded and post-processed to quantify the heat flux and the heat transfer coefficient. A heat transfer coefficient enhancement of 74% with the PDMS-coated surfaces compared to an uncoated surface has been achieved. Optical data of the surface wetting behavior was recorded and post processed to compare the experimentally determined drop size distribution with the Rose model.

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