Antifouling Performance of Nanopillar Polymer Surfaces: Insights from Surface Mechanics and Energy Based on Griffith’s Theory

Surface fouling severely limits the long-term functionality of artificial surfaces in biological applications. Here, we investigate the fouling-release (FR) performance of polymeric nanopillar surfaces (NPSs) featuring high-aspect-ratio nanopillars, using Chlorella vulgaris (C. vulgaris) as a model organism. Experimental analyses, including fluorescence imaging, visible absorbance spectroscopy (VIS), and scanning electron microscopy (SEM) observation, reveal that NPSs exhibit similar initial fouling levels to flat surfaces, but they show enhanced detachment behavior after mechanical or environmental stimulation. To explain these results theoretically, we propose a theoretical model that extends the Griffith-type fracture criterion to include nanoscale interfacial mechanics. The model incorporates critical surface energy, structural deformation, and contact geometry to predict the stress threshold required for fouling detachment. Finite element simulations confirm that nanopillar flexibility facilitates localized deformation under fouling stress, promoting release at reduced energetic cost. Importantly, our results suggest that fouling behavior is not solely governed by topography but also by the nonpolar component of surface free energy, which determines interfacial adhesion. This work offers an integrated theoretical and experimental perspective on fouling-release mechanics, contributing to the rational design of self-cleaning nanostructured surfaces for antifouling applications.