Controlled wettability of biphilic patterned surfaces for enhanced atmospheric water harvesting

Water is a vital component for all living organisms, yet persistent water scarcity remains a global challenge. One potential solution lies in replicating the atmospheric water collection mechanism observed in the Stenocara beetle, characterized by a dorsal surface featuring alternating hydrophilic and hydrophobic regions. In this study, we have designed and examined two distinct biphilic patterned surface configurations, integrating various technologies, to mimic the beetle's water collection strategy. Our investigation evaluates the efficiency of these surfaces in both capturing water from fog and condensing water from dew. For fog collection two parameters were the most impactful: the roughness and the wettability contrast between hydrophilic and hydrophobic zones. In contrast, dew condensation was influenced by additional parameters notably the patterns' size and density that directly affect the water contact angle. It is worth noting, however, that the optimal surface for fog collection may not necessarily coincide with the most effective surface for dew condensation. Furthermore, our research includes a comparative analysis between the theoretically predicted volume of water droplet departure and the empirically observed results.