Self-Stratifying Porous Silicones with Enhanced Liquid Infusion and Protective Skin Layer for Biofouling Prevention

Abstract

Liquid-infused silicones are a promising solution for common surface adhesion problems, such as ice accumulation and biofilm formation, yet they generally lack the tunability, mechanical durability and/or longevity essential for industrial applications. Self-stratifying porous silicones (SPS) infused with compatible silicone oil are developed as a passive strategy to address these shortcomings. Through emulsion templating, porosity is formed in the bulk polymer, providing increased free volume for oil infusion, while a non-porous skin layer is formed at the surface. The bulk porosity and pore size distribution of SPS are independently controlled by varying water and surfactant concentration respectively, leading to a higher volume of oil infusion and improved oil retention relative to an unmodified silicone. Despite a higher oil loading and bulk porosity, the skin layer provides liquid-infused SPS with a comparable surface elasticity to liquid-infused silicones. The potential of liquid-infused SPS as a nontoxic fouling release coating for marine applications is demonstrated using laboratory assays against a variety of soft and hard fouling organisms.