Non-toxic, non-biocide-release antifouling coatings based on molecular structure design for marine applications

TLDR

Marine biofouling is the unwanted accumulation of organisms on submerged surfaces, causing significant economic losses for ships, offshore platforms, pipelines, and other marine infrastructure by reducing performance and increasing maintenance costs. This review surveys recent advances in environmentally friendly antifouling coatings that avoid toxic biocides and instead rely on non‑biocide‑release principles for marine use. The authors examine two primary strategies—promoting detachment of fouling organisms and preventing their attachment—highlighting new approaches based on amphiphilic, superhydrophilic, and topographically structured surfaces that target the early stages of biofoulant adhesion. The review demonstrates that these molecular‑structure‑based surfaces effectively disrupt initial adhesion, offering a promising non‑toxic alternative for durable antifouling performance.

Abstract

Marine biofouling generally refers to the undesirable accumulation of biological organisms on surfaces in contact with seawater. This natural phenomenon represents a major economic concern for marine industries, e.g. for ships and vessels, oil and wind-turbine sea-platforms, pipelines, water valves and filters, as it limits the performance of devices, materials and underwater structures and increases the costs related to transport delays, hull maintenance and repair, cleaning and desalination units, corrosion and structure break-down. In the last few decades, many efforts have been spent into developing efficient antifouling (AF) surfaces (coatings) combining advances in materials science and recent knowledge of marine chemistry and biology. However, the extensive use of toxic and harmful compounds in the formulations raised increasing health and environmental concerns leading to stricter regulations which pushed marine industries to search for new AF strategies. This review presents the recent research progress made in green strategies for AF coatings using non-toxic, non-biocide-release based principles for marine applications. The two main approaches, detachment of biofoulants or preventing biofoulants attachment, are reviewed in detail and new promising routes based on amphiphilic, (super)hydrophilic, and topographic (structured) surfaces are highlighted. The chemical and physical aspects of the AF mechanisms behind the AF strategies reviewed are emphasized, with special attention to the early stages of biofoulant adhesion, keeping the focus on the materials' molecular structure and properties which allow obtaining the final desired antifouling behaviour.