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arXiv · 2311.13353

Durable, ultrathin, and antifouling polymer brush coating for efficient condensation heat transfer

Shuai Li·Cheuk Wing Edmond Lam·Matteo Donati·Kartik Regulagadda·Emre Yavuz·Till Pfeiffer·Panagiotis Sarkiris·Evangelos Gogolides·Athanasios Milionis·Dimos Poulikakos·Hans-Jürgen Butt·Michael Kappl
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Abstract

Heat exchangers are made of metals because of their high heat conductivity and mechanical stability. Metal surfaces are inherently hydrophilic, leading to inefficient filmwise condensation. It is still a challenge to coat these metal surfaces with a durable, robust and thin hydrophobic layer, which is required for efficient dropwise condensation. Here, we report the non-structured and ultrathin (~6 nm) polydimethylsiloxane (PDMS) brushes on copper that sustain high-performing dropwise condensation in high supersaturation. Due to the flexible hydrophobic siloxane polymer chains, the coating has low resistance to drop sliding and excellent chemical stability. The PDMS brushes can sustain dropwise condensation for up to ~8 h during exposure to 111 {\deg}C saturated steam flowing at 3 m/s, with a 5-7 times higher heat transfer coefficient compared to filmwise condensation. The surface is self-cleaning and can reduce bacterial attachment by 99%. This low-cost, facile, fluorine-free, and scalable method is suitable for a great variety of condensation heat transfer applications.

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Shuai Li, Cheuk Wing Edmond Lam, Matteo Donati, Kartik Regulagadda, Emre Yavuz, Till Pfeiffer, Panagiotis Sarkiris, Evangelos Gogolides, Athanasios Milionis, Dimos Poulikakos, Hans-Jürgen Butt, Michael Kappl. 2023-11-22. Durable, ultrathin, and antifouling polymer brush coating for efficient condensation heat transfer. https://doi.org/10.1021/acsami.3c17293

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