Biotechnology Enhances Marine Antifouling Coatings


Antifouling biotechnology developers I-Tech AB and RISE Research Institutes of Sweden recently announced they have developed a new method for introducing its barnacle repelling active agent into marine antifouling coatings.

Selektope, or medetomidine, is an active agent developed, patented and registered by I-Tech for use in antifouling coatings, reducing hard fouling on vessels and other underwater structures. The latest findings will reportedly expand the ways paint manufactures can work with the technology and pave the way for enhanced future hard biofouling prevention.

About the Research

I-Tech and RISE collaborated over the past five years on a series of projects to improve the use of Selektope in biocidal antifouling coatings for its barnacle fouling prevention characteristics. With the success of biocidal coatings dependent on the sustained control of biocide released at the coating surface, the team looked at previous elements that made antifouling coatings successful.

Selektope is currently delivered to the surface of self-polishing copolymer (SPC) antifouling coatings due to being held in the coating matrix via electrostatic interactions with metal pigments, allowing the technology to be evenly dispersed throughout the coating matrix and released at a sustained rate as the paint erodes or polishes.

However, the success of biocidal coatings is reportedly dependent on the sustained control of biocide release at the coating surface across the entire intended lifespan of a coating system. For large merchant ships, this period could be up to sixty months.

In other research, superior antifouling efficacy was achieved when a biocide was attached to a polymer chain with a covalent bond that was hydrolysable upon contact with water. Before the ban of tributyltin (TBT) use in 2008, this release mechanism is reportedly what gave TBT-containing coatings their success.

Researchers from I-Tech and RISE then began to look at ways of attaching Selektope to a co-polymer chain via the creation of Selektope-containing monomers that could be polymerized.

To test this idea, several coating SPC copper-free formulations on control panels were tested off the west coast of Sweden for 10 months, including:

  • Panel 1: SPC control coating with no Selektope;
  • Panel 2: SPC with pigment-bound Selektope and 1% zinc pyrethione;
  • Panel 3: SPC with polymer bound Selektope and 1% zinc pyrethione; and
  • Panel 4: SPC with polymer bound Selektope, no co-biocide.

Following this experiment, I-Tech and RISE reported that the control panel displayed heavy barnacle fouling whereas the panels coated with paints containing Selektope, both introduced via the traditional method and via the new method of attachment to a co-polymer chain, were barnacle-free. 

The researchers said these results provided proof of concept that attaching Selektope to a co-polymer for use in SPC antifouling coatings is possible.

“The successful creation of a Selektope-containing monomer that was then polymerised to create the co-polymer chain with Selektope attached is a significant achievement in the antifouling coatings sector as it expands the antifouling biocide toolbox,” commented Dr. Dan Isaksson, Research & Application Development Manager at I-Tech.

“This supports the coatings sector in its efforts to innovate around meeting future hard biofouling prevention needs. For these projects the focus was on SPC coatings. Proving this concept in silicone-based foul release coatings will be the next focus for I-Tech.”

The research findings were presented at the International Antifouling Conference earlier this year in Gothenburg, Sweden. The companies report that Selektope in SPC coatings has been used on over 1,000 vessels to-date.


Tagged categories: Antifoulants; Asia Pacific; Coating chemistry; Coating Materials; Coatings technology; Coatings Technology; EMEA (Europe, Middle East and Africa); Latin America; Marine Coatings; North America; Program/Project Management; Research and development; Ships and vessels; Z-Continents

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