Pushing the Limit of Beetle‐Inspired Condensation on Biphilic Quasi‐Liquid Surfaces

• Published in: Advanced functional materials 2023-03, Vol.33 (11), p.n/a
• Main Authors: Boylan, Dylan, Monga, Deepak, Shan, Li, Guo, Zongqi, Dai, Xianming
• Format: Article
• Language: English
• Subjects: Beetles; Beetle‐inspired surfaces; condensation; Contact angle; Droplets; Heat flux; Heat transfer; Heat transfer coefficients; Hydrophilicity; Liquid surfaces; Materials science; quasi‐liquids; Siloxanes; water sustainability; Wettability
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202211113

Massive studies concern the development of low‐carbon water and energy systems. Specifically, surfaces with special wettability to promote vapor‐to‐liquid condensation have been widely studied, but current solutions suffer from poor heat transfer performances due to inefficient droplet removal. In this study, the limit of condensation on a beetle‐inspired biphilic quasi‐liquid surface (QLS) in a steam environment is pushed, which provides a heat flux 100 times higher than that in atmospheric condensation. Unlike the beetle‐inspired surfaces that have sticky hydrophilic domains, the biphilic QLS consists of PEGylated and siloxane polymers as hydrophilic and hydrophobic quasi‐liquid patterns with the contact angle hysteresis of 3° and 1°, respectively. More importantly, each hydrophilic slippery pattern behaves like a slippery bridge that accelerates droplet coalescence and removal. As a result, the condensed droplets grow rapidly and shed off. It is demonstrated that the biphilic‐striped QLS shows a 60% higher water harvesting rate in atmospheric condensation and a 170% higher heat transfer coefficient in steam condensation than the conventional beetle‐inspired surface. This study provides a new paradigm to push the limit of condensation heat transfer at a high heat flux, which sheds light on the next‐generation surface design for water and energy sustainability. Beetle‐inspired surfaces with special wettability have the potential to improve the efficiency of low‐carbon water and energy systems. Here, the limit of beetle‐inspired condensation is pushed by utilizing a biphilic quasi‐liquid surface (QLS). It is demonstrated that the biphilic striped QLS showed a heat transfer coefficient 170% higher than the current beetle‐inspired surface in steam condensation.