A novel marine antifouling coating developed by a research team at South China University of Technology has reached large-scale commercial application across multiple sectors, including shipbuilding and maintenance, wave energy power generation platforms, undersea data centers, and marine ranches.

Zhang Guangzhao, a professor in the university's School of Materials Science and Engineering who leads the marine science and engineering research team, said the coating is playing an increasingly important role in advancing high-quality development of the ocean economy.

Unlike traditional antifouling products that depend on toxic biocidal substances to repel marine organisms, the new coating prevents biofouling adhesion and colonization through dynamic regeneration of the coating surface. It is formulated primarily with controllably degradable polymer materials, including polyester-polyurethane and polyester-polyacrylate.

In marine environments, seawater gradually hydrolyzes the ester groups within the polymer, triggering steady, controllable layer-by-layer degradation. This creates a continuously self-renewing surface that prevents fouling organisms — such as algae and barnacles — from forming stable attachments, delivering durable and efficient antifouling performance.

"The coating adopts fully controllable degradable polymer structures, which break down into harmless small molecules in seawater and completely avoid microplastic accumulation," Zhang explained.

To further enhance antifouling efficacy, Zhang's team incorporated natural-product-based antifouling ingredients into the polymer system, following an eco-innovative development philosophy described as "derive from the ocean, apply to the ocean."

"Compared with conventional coatings, this new formulation eliminates the use of heavy-metal biocides, features an environmentally compatible system and produces no adverse impacts on marine ecosystems," Zhang added.

Observations showed that each time fouling organisms attempted to anchor themselves, the constantly renewing substrate subtly changed in real time, making stable bio-attachment impossible. By precisely tuning the surface regeneration rate of the degradable polymers, the team achieved long-term, ecologically benign antifouling effects suitable for widespread marine engineering applications.

Conventional resins used in marine equipment antifouling coatings are non-degradable and pose potential microplastic pollution risks. Such coatings also release high levels of heavy-metal antifouling biocides, severely disrupting marine ecosystems. The environmental toll of conventional biocidal coatings has drawn increasing regulatory scrutiny worldwide. The International Maritime Organization's Anti-Fouling Systems Convention, which entered into force in 2008, banned organotin compounds such as tributyltin in ship coatings, and regulators in multiple jurisdictions continue to evaluate restrictions on copper-based biocides, the most common remaining active ingredient in mainstream antifouling paints.

Marine biofouling remains a global bottleneck restricting marine economic development and ecological governance, according to Zhang. Barnacles, algae, and oysters readily adhere to submerged structures such as ship hulls, propellers, and marine ranch cages. As biofouling accumulates, the additional weight can reach tens of kilograms per square meter in extreme cases. Often referred to as "marine psoriasis," biofouling significantly increases vessel resistance and fuel consumption, driving up operational costs across the marine industry while accelerating equipment corrosion and shortening service lifespans. The increased hull roughness caused by even light fouling also translates directly into higher greenhouse gas emissions from ships, linking antifouling technology to the maritime industry's broader decarbonization pressures under IMO targets to reduce annual greenhouse gas emissions from international shipping.

For decades, China lacked independent intellectual property rights and core manufacturing technologies for high-end polymer resins. As a result, the domestic marine antifouling coating market has been dominated by foreign suppliers, with 95 percent of the market reliant on imports — a technical gap that has constrained the upgrade and development of China's marine equipment industry. The commercialization of this domestically developed coating aligns with China's broader policy push to achieve self-sufficiency in advanced materials and reduce reliance on imported core technologies across strategic industrial sectors.

Official data shows that marine biofouling causes nearly $50 billion in economic losses worldwide annually, with China accounting for approximately $15 billion of the total, Zhang said.

Zhang's research team has partnered with multiple domestic enterprises to scale up production of the new coating to meet rising market demand. Current annual production capacity stands at 5,000 to 6,000 metric tons, and the coating has been widely applied in ocean-going shipping, marine energy facilities, offshore communication infrastructure, and marine ranches.

Key domestic end-users include COSCO Shipping, China State Shipbuilding Corporation, China National Offshore Oil Corporation, and LESSO, a global manufacturer of piping and building materials.

Source: China Daily via Hellenic Shipping News