Antifouling activity of PEGylated chitosan coatings: Impacts of the side chain length and encapsulated ZnO/Ag nanoparticles
Year: 2024
Type: article
Abstract: PEGylation is regarded as a common antifouling strategy and the effect is normally linked with surface hydrophilicity of the coatings. Herein, the biopolymer chitosan (CS) was grafted by polyethylene glycol (PEG) of different chain lengths (molecular weight 200, 4 k and 100 k Da) to verify if the hydrophilicity of CS-PEG coatings is crucial in determining antifouling activities and if PEG chain length influences biofouling in marine environment. Properties of copolymers such as melting points and crystallinity are affected by grafting PEG. The water contact angle (WCA) of CS-PEG coatings increases with the chain length of grafted PEG, from 27° to 58°. Photocatalyst of zinc oxide-silver (ZnO/Ag) was also studied and its embedment (2 % to CS-PEG) renders the surface of CS-PEG coatings more hydrophobic with WCA increased from 52° to 86°. Antibacterial, anti-diatom, and anti-biofilm activities of the coatings were evaluated in natural sea water. The bacterial density on CS-PEG coatings was dramatically reduced to 4 × 10 4 compared to the control of 7 × 10 4 ind/mm 2 , and further to 2 × 10 4 for CS-PEG-ZnO/Ag coatings. CS-PEG coatings also strongly inhibit diatoms (120–200 ind/mm 2 ), but the inclusion of ZnO/Ag did not obviously enhance such effect (50–150 ind/mm 2 ). The findings provide useful insights for designing polymer-based antifouling coatings. • CS-PEG copolymers with different lengths of PEG side chain were prepared and studied. • Water contact angle (WCA) of CS-PEG coatings varies with PEG chain length. • Chain length of CS-PEG has impacts in anti-diatom activity and biofilm formation. • Photocatalyst ZnO/Ag significantly enhances the inhibition of bacteria and biofilm formation, but not anti-diatom properties. • Chain length and crystallinity of copolymers, not surface hydrophilicity, determines the antifouling effect of CS-PEG coatings.
Authors: Dongkun Yu, Fei Ye, Sergey Dobretsov, Joydeep Dutta
Institutions: KTH Royal Institute of Technology, Sultan Qaboos University
Language: English
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,260
OpenAlex ID: W4403117701