Design and fabrication of microstructured PDMS surfaces for antifouling and drag reduction

Marine biofouling on ship hulls substantially increases hydrodynamic drag and operational costs. This study selects the barnacle, a sessile crustacean with strong adhesion ability, and develops polydimethylsiloxane films patterned with micro-cylinders to achieve dual-functional antifouling and drag reduction based on the barnacle larvae dimensions and hydrophobic principle. Bioassays with barnacle cyprid larvae demonstrated that the microstructured surfaces significantly inhibited settlement, achieving an antifouling rate of 59%. Rotational drag tests further revealed a maximum drag reduction of 7.2% at 100 rpm. To elucidate the physical mechanisms, computational fluid dynamics simulations using the volume of fluid model were conducted. The numerical results verified the stability of the entrapped gas-liquid interface within the microstructures and revealed a substantial reduction in near-wall turbulence intensity and shear stress, quantitatively validating the slip-effect mechanism. These combined experimental and numerical results demonstrate the potential of engineered microstructured surfaces for marine antifouling and drag reduction applications.