An international group of engineers has come up with a groundbreaking and adaptable approach for producing aluminum surfaces with specific topographical patterns. This advancement improves the movement of liquids, which is crucial for uses in cooling electronics, self-cleaning technologies, and anti-icing systems. This study, recently published in Langmuir, was conducted by teams from Rice University and the University of Edinburgh as part of the Rice-Edinburgh Strategic Collaboration Awards program. It showcases how affordable vinyl masking methods can generate surfaces with high-definition wettability variation, setting the stage for enhanced phase-change heat transfer applications.
The research team introduced an inventive approach using blade-cut vinyl masks paired with readily available lacquer resin, alongside scalable physical and chemical surface treatments to create textured aluminum surfaces. These surfaces display varying wettability, which greatly boosts droplet removal during condensation. The design features details as fine as 1.5 mm, offering a spectrum of wettability characteristics—ranging from superhydrophobic to hydrophilic—that depends on the treatment applied.
“This technique marks a vital advancement in customized surface engineering,” stated Daniel J. Preston, assistant professor of mechanical engineering at Rice and co-corresponding author of the publication alongside Geoff Wehmeyer, also an assistant professor at Rice, and Daniel Orejon from the University of Edinburgh. “By allowing precise manipulation of surface wettability and thermal properties, we are unlocking new possibilities for the large-scale production of advanced heat transfer surfaces.”
The study used a multi-phase process to create and study the patterned aluminum surfaces. Initially, vinyl masks were applied to polished aluminum substrates, which underwent a two-stage etching procedure to produce micro- and nanotextured areas. Subsequently, advanced imaging methods were employed to assess the resolution and wettability characteristics of the patterns. Performance tests through condensation visualization experiments showed that the patterned surfaces significantly improved droplet shedding compared to uniform surfaces. Furthermore, thermal emissivity mapping via infrared thermography highlighted marked differences in emissivity between smooth and textured sections, emphasizing the surfaces’ potential for sophisticated thermal management applications.
“Aluminum is a key material in thermal management technologies, such as heat exchangers, because of its excellent conductivity, lightweight, and affordability,” remarked Wehmeyer. “Our method enhances its functionality by adding surface patterning that is both economical and scalable, allowing engineers to adjust condensation heat transfer effectively. This collaboration merged the expertise of Edinburgh and Rice to develop and analyze these advanced surfaces.”
The outcomes have considerable implications for industries reliant on phase-change heat transfer, with the potential to impact everyday technologies. In the realm of electronics cooling, improved droplet shedding diminishes thermal resistance due to large droplets during condensation, possibly leading to innovative cooling methods for data center servers or other electronic devices that require efficient heat dissipation to avoid overheating. Customized thermal emissivity patterns optimize heat dissipation in high-temperature settings, benefiting systems like automotive engines and aerospace components. Additionally, superhydrophobic zones facilitate water removal, preventing ice buildup on essential surfaces such as airplane wings, wind turbines, and power lines in cold weather. These developments provide practical solutions to boost the performance and reliability of technologies that society relies on daily.
“Conventional techniques like photolithography tend to be costly and limited to small areas,” noted Preston. “Our approach utilizes inexpensive, accessible materials to create detailed patterns over larger surfaces, making it ideal for industrial use and a promising method for designing the next generation of condensers and heat exchangers.”
The lead authors of this research include Trevor Shimokusu (a Rice mechanical engineering doctoral graduate, now a faculty member at the University of Hawaii) and Hemish Thakkar (a Rice graduate with degrees in chemistry and mechanical engineering, now pursuing a doctorate at Princeton University).
This research received support from the Rice-Edinburgh Strategic Collaboration Award program, a NASA Space Technology Graduate Research Opportunities grant, and funding from the National Science Foundation.
