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Siloxane-Polyurethane Coatings with Hydrophilic Side Chains for Marine Fouling Release Applications - Available Technologies - NDSU Research Foundation

Siloxane-Polyurethane Coatings with Hydrophilic Side Chains for Marine Fouling Release Applications

DESCRIPTION

This invention is a curable amphiphilic polyurethane coating designed to prevent marine biofouling using a combination of hydrophobic and hydrophilic components. The formulation includes a pre-polymer made from:

a hydrophilically modified polyisocyanate (such as PEG- or sulfobetaine-modified isocyanates),
polyethylene glycol (PEG),
polydimethylsiloxane (PDMS), and
an optional catalyst.

This pre-polymer is combined with a polyol, a polyisocyanate crosslinker, and at least one amphiphilic additive (such as PEG-modified siloxane). The result is a polyurethane coating that forms an amphiphilic surface after curing—meaning it contains both water-attracting (PEG/sulfobetaine) and water-repelling (PDMS) regions. This combination:

discourages initial attachment of proteins and microorganisms, and
makes it easier to remove fouling organisms that do attach.

The formulation may also include catalysts, solvents, and pot-life extenders to tailor working time and application properties. It can be applied to various surfaces and cured under ambient or elevated temperatures.

This coating is intended as a non-toxic alternative to biocidal antifouling coatings, combining surface chemistry and polymer science to passively resist and release marine biofouling.

Benefits

Non-toxic fouling resistance: PEG and sulfobetaine create hydration layers that prevent biofilm formation without biocides.
Fouling-release functionality: PDMS reduces surface energy, enabling easy removal of attached organisms.
Amphiphilic design: Surface rearranges in water to present an optimal balance of hydrophilic and hydrophobic domains.
Durable polyurethane network: Strong, chemically crosslinked system ensures mechanical stability in harsh environments.
Formulation flexibility: Adjustable PEG/PDMS content and optional solvents or additives support diverse applications.
Compatible with standard equipment: Cures under ambient or elevated conditions, easy to integrate into current coating workflows.

Applications

Marine vessel hulls: Reduce drag and fuel consumption by minimizing marine growth.
Offshore structures: Long-term fouling protection for oil rigs, wind turbines, and underwater pipelines.
Aquaculture equipment: Clean, non-toxic coatings for fish cages, nets, and tanks.
Marine sensors and instruments: Prevents data distortion from biofilm buildup.
Defense and naval use: Supports low-maintenance, operational readiness for naval ships and submarines.
Ports and docks: Protects submerged surfaces in harbors and moorings from biofouling.