Journal article
Field study of the long-term release of block copolymers from fouling-release coatings
Department of Chemical and Biochemical Engineering, Technical University of Denmark1
CHEC Research Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Hempel AS3
The Danish Polymer Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark4
The Hempel Foundation Coatings Science and Technology Centre (CoaST), Department of Chemical and Biochemical Engineering, Technical University of Denmark5
The addition of block copolymers (i.e. oils) is a common technique to enhance the biofouling-resistance properties of poly(dimethylsiloxane) (PDMS)-based fouling-release coatings. These copolymers diffuse from the bulk to the surface of the coating, thus modifying the properties of the surface and providing fouling-resistance properties.
Upon release, dissolution or degradation of copolymer molecules at the surface, new molecules can diffuse from the bulk of the coating and cover the surface. Therefore, the long-term performance of these coatings is dependent on the stability and release rate of copolymer molecules from the surface.
A method was developed to quantify the concentration of PDMS-based block copolymers from fouling-release coatings. About 300 experimental coatings exposed to seawater for up to 5.2 years were included in the analysis. The results showed that the loss of copolymer (in % on a weight basis) is significantly higher in warm waters, while the initial copolymer concentration in the coating does not have any effect for copolymer concentrations between 1 and 7 wt%.
In short-term exposure, it was found that loss of copolymer was much higher in coatings containing small amounts of an organic biocide (copper pyrithione). Conversely, biocide-containing coatings displayed larger copolymer retention values in long-term experiments. Opposite results were obtained for biocide-free coatings, suggesting that the addition of the organic biocide alters the release profile of copolymers from fouling-release coatings.
Finally, the potential of long-term field-studies is discussed, as compared to short-term laboratory experiments usually performed within fouling-release coatings studies.
Language: | English |
---|---|
Year: | 2017 |
Pages: | 101-108 |
ISSN: | 1873331x and 03009440 |
Types: | Journal article |
DOI: | 10.1016/j.porgcoat.2017.07.001 |
ORCIDs: | Kiil, Søren |