Computational fluid dynamics analysis of superhydrophobic and superhydrophilic micro-textures for biofouling mitigation

• Different micro-textured superhydrophobic and superhydrophilic were designed. • Density and shapes of micro-textured were investigated. • Contact angle 150° and 20° were chosen for superhydrophobic and superhydrophilic. • Maximum spreading diameter was selected to have a comparison analysis. Micro-texturing has been studied for many decades as a passive antifouling technology. However, most studies have been experimental in nature and lack an informed basis for the selection of the micro-texture architecture. The herein reported preliminary numerical studies explored micro-textured superhydrophobic and superhydrophilic surfaces for mitigating biofouling and related effects, such as Microbial Induced Corrosion (MIC). Surface wettability manipulation is a key mitigation strategy for these issues. A computational model was developed to simulate the spreading behaviour of water droplets (an indicator of wettability) on three micro-textures (cubic, cylindrical, and hemispherical), with varying inter-pillar distances (10, 20, and 30 μm) for both superhydrophobic and superhydrophilic surfaces, with contact angles of 150° and 20°, respectively. Results showed lower Maximum Spreading Diameters (MSD) on the superhydrophobic models, compared to a flat surface. Cubic micro-textures with larger inter-pillar distances reduced MSD by 54.42%, suggesting enhanced water repellence and potentially preventing biofouling and closed-related effects such as MIC. Conversely, all superhydrophilic models had higher MSDs and formed an electrochemically-bound epitaxial aqueous surface layer which could act as a physical and interfacial energy barrier to bio-attachment. Hemispherical morphologies increased the MSD by 68.92%. The findings highlight the criticality of informed computational studies in biomimetic antifouling research whilst also demonstrating the potential benefits of micro-texturing as part of passive antifouling surface technology.