Over time; commercial ships, yachts and all other floating platforms wet surfaces are covered with weeds, seashells such as mussels, barnacles. This phenomenon called biofouling.
Because of this phenomenon, a new rough surface structure has been formed. Resulting from this situation: friction coefficient of the vessel increases whereas maneuverability decreases. It causes significant increases in the operating costs of the vessel.1To prevent from that situation with the development of chemical industry, antifouling paint contains Tributyltin (TBT) started to be used since the 1960s.2 When the investigations have proven that TBT based paints cause significant long-term damage to marine life, especially marine organisms endocrine system TBT based antifouling paints has been banned since 1 January 2008.
Therefore, the new generation antifouling paints containing zinc oxide started to use; which has similar antifouling performance but has the less harmful effect on marine life.3 But because of its harmful and long-standing effects on the marine environment; the allowed amount of the zinc oxide that passes to water from the paint is decreased from year to year in many countries. And in near future usage of zinc oxide at marine paints will be completely banned.4 For this reason, a new coating material must be developed to protect the wet surface as much as possible from foreign organisms and keep it in a smooth structure. There are many studies on antifouling properties of hydrogels and other substances.
On the basis of the idea of using hydrogels as a new coating material: fouling organisms do not adhere to the skin of othersea creatures (fish, algae etc.) but they settle down to rocks and similar seashells and other hard surfaces such as metals. Hydrogels attract attention with their similarity to the skin of sea creatures.
5 For example, Katsuyama found that polyelectrolyte hydrogels avoid germination process against algae zoospores 6. Rasmussen described toxic effects of some natural polymer gels and the chemically cross-linked polyvinyl alcohol (PVA) gels to barnacle cypris7. Cao founded that of polymer coatings of polysaccharides shows resistance to the adhesion of protein, algae, and barnacles 8 In Takayuki Murosaki et.
al’s studies, various hydrogels have been investigated as a surface coating material on the wet surfaces of vessels against fouling organisms. The study of the laboratory and the field were mostly focused on the effects on the barnacles. During the investigations, hydrogels with different active groups having both single network structure and double network structure were used. Examples are PAAm, PDMAAm, PHEMA, PHEA, PNAAMPS, PAMPS, PNaSS, PDMAPAAQ, PAAc / PAAm and PAMPS / PAAM hydrogels. It is also used in hydrogels having active groups -OH, -SO3, NH2, N (CH3) 2, CH3, N (CH3) In the laboratory tests, test setups were made by covering the floor with hydrogels such as PAMPS / PAAm in the test pools produced from polystyrene and the settlement activities of the barnacle were observed 5 In the field tests, PAMPS / PAAm double netted hydrogels and polyethylene plates as a control group were fixed to the stainless surface and left in the sea. 9 In addition, the swelling properties and the properties of the pores on the polyacrylamide-dextran hydrogels were investigated according to the temperature of synthesis. In the experiments, PAAm / Dx hydrogels were synthesized by crosslinking copolymerization method at 3 different temperatures (+25, +5, -18).
10 Also in another study various double-walled hydrogels (mostly hydrophilic) were obtained. The strengths of these hydrogels against tensile forces and pressures were investigated and compared with single-walled hydrogels. In addition, the resistance of the obtained hydrogels to wear has been investigated. 11 From the experiments about using hydrogels as surface protection materials showed that hydrogels with hydroxyl and sulfonic groups have been found to be a successful antifouling coating material. It has been observed that the electric charges of hydrogels have no effect in protecting the surface from living organisms. The longer the alkaline chain is, the greater the antifouling effect of the hydrogel is observed.
Negative results were obtained when hydroxides and sulfonic acid groups were used together. 5This study consist of three main stages. The first stage is that antifouling composites will be selected to use in experiments with the help of the data obtained from the literature review. Then the composites will be produced in the laboratory. Changes in their optical properties during the gelation, drying and swelling process will be studied with the steady-state fluorescence technique.
After obtaining results, diffusion and desorption coefficients will be calculated. And the final step is to determine the antifouling properties of the composites. Results from Laboratory and field tests will be used to determine antifouling properties of the composites.