Interfacial engineering of hierarchical superhydrophobic anti-fouling surfaces

Abstract

Engineering bio-inspired antifouling surfaces is of importance for a wide range of applications. Water-repellent surfaces, owning so many unique properties such as self-cleaning, anti-contamination, and drag reduction are highly desirable to achieve this goal. Herein we report the development of a novel superhydrophobic surface featured with hierarchical architecture that exhibits enhanced antibacterial activity. The superhydrophobic surfaces is patterned with lattice arrays of submillimetre-scale posts decorated with uniformed nanotextures. We found that an impacting drop could detach from the surface close to its maximum lateral extension with a pancake-like shape, resulting in a four-fold reduction in the contact time compared to that on the conventional superhydrophobic surfaces.We also found that, on the tilted surface with an appropriate tilt angle, the impacting drop bounced off the surface in a pancake shape with a much shortened contact time and left the field of view before bouncing again. This exclusive property, characterized by minimized contact of the liquid with the solids, not only endows a minimal bacterial adhesion in the static condition, but also in the dynamic conditions relevant to practical applications. We envision that the antibacterial surface reported here will find promising applications in dropwise condensation, heat exchangers, and biosafety where requires environmentally friendly antifouling coatings.