Antifouling bio-coatings (marine)

01Overview and value chain

Markers: [EC: Biocidal Products Regulation (BPR) & marine-coating VOC standards | OECD: bio-materials | Regulator: EPA (US), REACH (EU), NMPA (CN)]

Marine antifouling bio-coatings prevent algae, mussels and barnacles from colonizing ship hulls without relying on the toxic heavy-metal biocides (copper, tributyltin) that dominated the sector for decades and caused lasting damage to port and estuary ecosystems. The leading commercial route is the self-polishing copolymer (SPC), a resin that hydrolyzes slowly and evenly in seawater under hull friction to release a controlled, steady dose of repellent; AkzoNobel’s International brand launched its Intersleek 2120 silicone foul-release coating in June 2026, while Jotun’s Seaquantum Ultra S uses a one-component, chemically hydrolysing silyl-acrylate chemistry for stable self-polishing. Hempel completed the first newbuilding application of its next-generation Hempaguard NB silicone hull coating in 2026, applying it directly during vessel construction in partnership with Maersk and Yangzijiang Shipyard rather than only as an in-service retrofit. Biomimetic surface texturing (shark-skin- and lotus-leaf-inspired micropatterns) and enzymatic barriers that break down the protein “glue” barnacle larvae use to attach are the two fastest-growing biological alternatives to silicone/SPC chemistry, and reduced hull friction from any of these routes can cut a vessel’s hydrodynamic drag enough to lower fuel burn and CO2 emissions.

The key directions of marine antifouling bio-coatings are:

1. Self-polishing copolymers (SPC): resin matrices that hydrolyze at a controlled rate in seawater, continuously renewing a smooth, repellent-releasing surface as the ship moves.
2. Natural bioactive repellents: compounds such as zosteric acid (from seagrass), tannins and chitosan used in place of copper or organotin biocides.
3. Biomimetic surface texturing: micro-patterned surfaces inspired by shark skin or lotus leaves that physically discourage larval settlement without releasing any biocide.
4. Enzymatic antifouling: protease and galactosidase enzymes embedded in the coating that break down the protein adhesive barnacle larvae use to attach to steel.

Sectoral value chain

[Repellent/Enzyme Screening] ──> [Copolymer Synthesis & Formulation] ──> [Self-Polishing Matrix Production]
                                                                                  │
                                                                          (Airless spray in drydock)
                                                                                  │
                                                                                  ▼
[In-Service Fouling Monitoring] <─── [Hull Coating Application]

Value chain levels

Cross-cutting technologies of the sector:

• Self-polishing copolymers (SPC): polymer matrices that hydrolyze slowly and evenly under frictional shear in seawater, keeping a fresh, repellent-releasing surface exposed throughout a hull’s service life.
• Enzymatic antifouling barriers: protease and galactosidase enzymes incorporated into the coating that degrade the protein adhesive barnacle larvae use to attach, preventing settlement without a biocide.
• Biomimetic micro-texturing: shark-skin- or lotus-leaf-inspired surface patterns that physically interfere with larval settlement and biofilm formation.

02US

The US focuses on biomimetic and enzymatic antifouling research, with the Navy as a leading institutional driver of durable, non-toxic hull-coating development.

biomimetic surface texturing, Navy-funded R&D, non-toxic coating standards

• Naval research funding: the US Navy is a major funder of research into durable, non-toxic antifouling coatings for its fleet, driving work on biomimetic surface textures and enzymatic barriers as copper/TBT alternatives.
• Biomimetic micro-texturing: US-developed shark-skin-inspired micropatterned films are used to physically discourage bacterial biofilm formation and larval attachment without releasing any biocide.
• Regulatory posture: the EPA regulates antifouling paint biocides under FIFRA, pushing the market toward silicone foul-release and biological-repellent chemistries as copper-based paints face tightening restrictions.

03CN

China leads in coating deployment scale as home to the world’s largest shipyards, while its marine research institutes develop lower-cost natural-repellent coating chemistries.

large-scale shipyard deployment, seaweed/chitosan-based repellents, green-shipping standards

• Institute of Oceanology, Chinese Academy of Sciences (Qingdao): its Marine Corrosion, Fouling and Protection Materials research group has developed multifunctional protective coatings — including a photothermal superhydrophobic coating combining anti-icing and anti-corrosion functions for marine aluminum alloys, published in Materials Today Physics in 2026.
• Shipyard scale: China’s shipyards apply antifouling coatings at the largest volume of any country, giving domestic natural-repellent formulations (seaweed-extract and chitosan-based) a large addressable retrofit and newbuilding market.
• Green-shipping standards: China’s Ministry of Transport has introduced national green-shipping standards pushing shipowners toward low-VOC, heavy-metal-free coatings.

04EU

The EU is the commercial center of the antifouling coatings industry, driven by strict Biocidal Products Regulation (BPR) limits on copper-based paints in the Baltic and North Seas.

BPR-driven silicone foul-release systems, self-polishing copolymer leadership, newbuilding integration

• AkzoNobel (International, Netherlands): launched the Intersleek 2120 silicone foul-release coating in 2026 and joined RightShip’s Zero Harm Innovation Partners Program to advance safer, cleaner marine coatings.
• Jotun (Norway): markets the Seaquantum Ultra S self-polishing silyl-acrylate antifouling coating and unveiled its expanded Hull Performance Solutions (HPS 2.0) coating system in 2026.
• Hempel (Denmark): completed the first newbuilding application of its next-generation Hempaguard NB silicone hull coating in 2026, integrating it directly into the shipbuilding process with Maersk and Yangzijiang Shipyard rather than applying it only as a retrofit.

05Leading companies and research institutes

06Tech stack and innovations

The antifouling bio-coatings stack pairs a biologically derived active ingredient or surface pattern with a durable polymer delivery matrix.

1. Self-polishing copolymer (SPC) matrices:
   • A silyl-acrylate or silicone-based binder hydrolyzes at a controlled rate under seawater flow shear, continuously exposing fresh, repellent-releasing surface as the outer layer wears away.
   • This mechanism is what allows silicone foul-release systems like Intersleek and Seaquantum to maintain performance across multi-year drydocking intervals.
2. Biomimetic surface texturing:
   • Micro-scale surface patterns modeled on shark skin or lotus-leaf micro-roughness physically disrupt the settlement cues that algae spores and barnacle larvae rely on.
   • Because these surfaces work through geometry rather than chemistry, they avoid biocide-release regulatory hurdles entirely.
3. Enzymatic and natural-repellent additives:
   • Protease and galactosidase enzymes embedded in a coating degrade the protein adhesive barnacle larvae secrete, preventing attachment without a toxic biocide.
   • Natural repellents such as zosteric acid (from Zostera marina seagrass) and chitosan provide a biodegradable alternative to copper/organotin biocides.

07Value chains and production pipelines

Industrial pipeline of self-polishing antifouling coating production and application

┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Repellent extraction    │ ───> │ 2. Copolymer synthesis     │
│    (e.g., zosteric acid)   │      │    (silyl-acrylate binder) │
└───────────────────────────┘      └───────────────────────────┘
                                                 │
                                                 ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Hull blast-cleaning     │ <─── │ 3. Paint dispersion        │
│    (Sa3 standard)          │      │    (dissolver mixing)      │
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. Airless spray           │ ───> │ 6. In-service fouling      │
│    application (drydock)   │      │    monitoring              │
└───────────────────────────┘      └───────────────────────────┘

Stage 1: Repellent extraction

Zosteric acid is extracted from Zostera marina seagrass by aqueous-alcohol extraction followed by crystallization, yielding the natural antifouling active ingredient.

Stage 2: Copolymer synthesis

A silyl-acrylate copolymer binder is synthesized in a polymerization reactor, engineered to hydrolyze at the rate needed for controlled, even release in seawater.

Stage 3: Paint dispersion

The copolymer binder, repellent, plasticizers and fillers are mixed in high-speed dissolvers until a homogeneous emulsion with sub-15-micron particle size is achieved.

Stage 4: Hull blast-cleaning

The vessel is drydocked and its steel hull is abrasive-blasted to bare metal (the Sa3 cleanliness standard), removing old coating and rust to ensure adhesion.

Stage 5: Airless spray application

An anticorrosive primer, a tie-coat, and the final antifouling layer are applied in sequence by airless spray equipment to a total dry-film thickness of roughly 150-200 micrometers.

Stage 6: In-service fouling monitoring

Hull condition and fouling accumulation are tracked across voyages, feeding back into fuel-efficiency and drag-performance data used to schedule the next drydocking.