Design of anti-biofouling Lubricant-Impregnated Surfaces (LIS) robust to cell-growth-induced instability

Abstract

Unwanted deposition of cells on wetted solids, so-called biofouling, is a serious operational and environmental threat in many underwater and biomedical applications. Over the last decade, Lubricant-Impregnated Surfaces (LIS) has been one of the popular remedies, owing to its unique oil layer that separates solid from cellular media giving no chance for cells to foul. However, a critical bottleneck to this solution has been that retention of the oil could never be permanent, which shortened its anti-fouling efficacy. While understanding the root cause of this oil loss significantly helps prevent such failure, the loss mechanism has not received much attention to date. In this study, we show that secretion of biomolecules from aquatic cells and subsequent change in interfacial tension of the surrounding media can delaminate the oil film, resulting in gradual deterioration of anti-biofouling capability of LIS. We establish a correlation between the decrease in interfacial tension and observed wetting transitions of LIS over the fouling test period. We also visualize the cell medium - oil interface to confirm final wetting states of LIS in situ. We further measure mobility of various algae droplets on such surfaces and scale forces to confirm presence of line force specific to each wetting state. Finally, we propose a LIS regime map that helps determine the design of LIS that can resist oil loss in aquatic cellular environments, increasing long-term anti-biofouling efficacy.