Water capillary transport: from the desert beetle to industrial devices

The results of the research published in ACS Applied Materials & Interfaces
desert beetle, drops on surface

Directional liquid transport still represents a challenge in many engineering applications. Managing millimeter-scale water flows, for example, is crucial for proton exchange membrane fuel cells, digital microfluidic devices, thermal management of electronic components, and water harvesting. It can also be useful for mitigating the undesired effects of water and ice by removing water from exposed surfaces of sensors and devices operating in extreme environments.

In this context, a collaboration has emerged between FT Technologies UK (England, led by Dr. Tanmoy Maitra), the University of Graz (Austria, Prof. Anna Maria Coclite), and the Department of Materials Science at the University of Milano-Bicocca (SEFI Lab, Prof. Carlo Antonini). All institutions are part of the SURFICE (Smart surface design for efficient ice protection and control) training network, a project funded by the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie actions.

The collaboration has led to the development of surfaces with contrast wettability, inspired by the Namib desert beetle Stenocara sp., which can be used to create microfluidic devices capable of passively transporting water through capillarity. Perhaps the most innovative aspect of this study is the use of aluminum alloy as the base material, which is essential for the industry. Moreover, the fabrication of micrometric channels is achieved through a laser system without the use of environmentally harmful chemical agents. Therefore, the manufacturing process is scalable and enables the production of eco-friendly and durable surfaces, as confirmed by both laboratory-based artificial tests and a one-year exposure to natural weathering in Miami, Florida, USA, a location with conditions four times more aggressive than those in Europe.

The study has been reported in the paper entitled "Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces" (DOI: 10.1021/acsami.3c03840) published in the prestigious international journal ACS Applied Materials & Interfaces (Impact Factor 10.383, Journal Citation Report (Clarivate Analytics, 2021)).

"This work demonstrates that collaborations between academia and industry can achieve results that have both high scientific values, as demonstrated by the publication in the journal ACS Applied Materials & Interfaces, and real industrial relevance", commented Luca Stendardo, a doctoral student at the Department of Materials Science and first author of the article along with Theodoros Dimitriadis from FT Technologies.

From now until the end of 2024, within the SURFICE project, research activities will continue to develop new materials and devices that reduce or control ice formation, with applications related not only to sensing but also to aeronautics and energy systems.