Marine Antibiofouling Research Articles

Inhibition of Marine Biofouling by Use of Degradable and Hydrolyzable Silyl Acrylate Copolymer

Silyl acrylate copolymers are promising materials for marine antibiofouling. However, their structures need optimizing to improve their erosion and mechanical properties. We have prepared copolymer of 2-methylene-1,3-dioxepane (MDO), tributylsilyl methacrylate (TBSM) and methyl methacrylate (MMA) via radical ring-opening copolymerization. Such polymer has a degradable backbone and hydrolyzable side groups. Our study demonstrates that as the ester units in the backbone increase, the degradation rate increases but the swelling decreases in seawater. The degradation is controlled by the polymer composition or the molar ratio of the ester units in the backbone to the silyl ester side groups. Moreover, such polymer can serve as a carrier and controlled release system for organic antifoulants. Marine field tests show that the system consisting of the copolymer and organic antifoulant has good antifouling performance depending on the polymer composition. It can effectively inhibit the colonization and growth of marine organisms when MDO content is above 20 wt %.

Poly(dimethylsiloxane)-Based Polyurethane with Chemically Attached Antifoulants for Durable Marine Antibiofouling.

Marine biofouling is a problem for marine industry and maritime activities. We have prepared polyurethane with poly(dimethylsiloxane) (PDMS) main chains and N-(2,4,6-trichlorophenyl) maleimide (TCM) pendant groups via a combination of a thiol-ene click reaction and a condensation reaction and studied its properties. The polymer has low surface energy and a high water contact angle. When TCM content in bulk is high enough, sufficient antifoulant groups can be exposed on the surface. Our study reveals that such polymeric surface can effectively inhibit the adhesion and colonization of marine organisms such as bacteria (Micrococcus luteus), diatom Navicula, and barnacle cyprids. Particularly, marine field tests demonstrate that the polymer has excellent antibiofouling performance in 110 days.

Degradable Polymer with Protein Resistance in a Marine Environment.

Protein resistance is the central issue in marine antibiofouling. We have prepared poly(ε-caprolactone) (PCL)-based polyurethane with 2-(dimethylamino) ethyl methacrylate (DEM) as pendant groups by a combination of the thiol-ene click reaction and the condensation reaction. By the use of quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR), we have investigated the adsorption of fibrinogen, bovine serum albumin (BSA), and lysozyme on the polymer surface. The polymer exhibits protein resistance in seawater but not in fresh water because DEM pendant groups carry net neutral charges in the former. The evaluation of antibacterial adhesion of the polymer by using Micrococcus luteus demonstrates that the polymer can effectively inhibit the settlement of marine bacteria. Our studies also show that the polymer is degradable in marine environments.

Multiscale hairy surfaces for nearly perfect marine antibiofouling.

Natural fur with a high density of soft hair fibers was selected as a model hairy surface to study the interaction of microalgae/zoospores with this biomimetic surface covered with "hairs". The synergistic antifouling (AF)/fouling-release (FR) effect of the hair fibers and the surface chemical composition after grafting polymer brushes onto the hair fibers using surface-initiated atom transfer radical polymerization (SI-ATRP) was also explored. A series of laboratory static and dynamic settlement assays with microalgae and zoospores were carried out to systematically investigate the relationship between the modified poly-sulfopropyl methacrylate (PSPMA) brushes, the density/shape/length of the hair fibers and the AF/FR properties. The results indicate that the polymer brush-modified hairy surface can be effective against the settlement of microalgae/zoospores in different bioassays, especially in dynamic settlement assays. In general, hairy surfaces of higher hair fiber density, and with longer fibers, tend to display lower settlement of microalgae/zoospores, and the surface modification of the hair fibers with PSPMA brushes can strongly improve their AF/FR properties.