Degradable polymers with protein resistance can find applications in antibiofouling. We have prepared copolymer of 2-methylene-1,3-dioxepane (MDO), 2-(dimethylamino) ethyl methacrylate (DEM) and 3-(methacryloxypropyl) trimethoxysilane (KH570) via radical ring-opening polymerization, where MDO, DEM, and KH570 make the polymer degradable, protein resistant and self-cross-linkable, respectively. Our studies demonstrate that the self-cross-linking significantly improves the coating ability of the polymer with controlled biodegradation in seawater. We have investigated the adsorption of fibrinogen, bovine serum albumin and lysozyme on the self-cross-linking polymer surface as a function of its composition by use of quartz crystal microbalance with dissipation (QCM-D). It shows the polymer network can resist the adsorption of proteins in seawater. The antibacterial adhesion of the polymer network was evaluated by using Micrococcus luteus (M. luteus) and Pseudomonas sp., revealing that the polymer network can effectively inhibit the settlement of marine bacteria.

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.

•The degradable polyurethane-organic antifoulant system has good antibiofouling performance and excellent adhesion to the substrate.•Polyurethane with a certain composition degrades in marine environment at a constant rate.•The release rate can be regulated by varying the degradation rate or composition of the polymer.Controlled release of antifoulant is critical for marine antibiofouling. We have prepared polyurethane with degradable polyester segments consisting of poly(ethylene adipate) (PEA), poly(1,4-butylene adipate) (PBA) or poly(1,6-hexamethylene adipate) (PHA) and used it as the release system for organic antifoulants. The degradation rate of the polyurethane increases with the content of the degradable segments. On the other hand, as the segments change from PEA, PBA to PHA, the degradation rate decreases because the crystallinity increases but the ester group density decreases. Such degradable polyurethane allows the antifoulants to release at a constant rate, where the release rate can be regulated by varying the polyester segments. Marine field tests reveal that the polyurethane-antifoulant system has good antifouling performance. Particularly, the degradable polyurethane exhibits excellent adhesion to the substrate ensuring the long duration of the system.Polyester based polyurethane has been prepared and used it as carrier and release system of organic antifoulants. Such degradable polyurethane allows the antifoulants to release at a constant rate. The system exhibits excellent antifouling performance and adhesion to the substrate.

Antimicrobial coating is of great important in leather finishing. Herein, we report a newly synthesized polyurethane with zwitterionic sulfobetaine side groups and evaluate their performance in the antifouling leather coatings. The microstructure of the synthesized zwitterionic polyurethane (iNPU) films has been examined by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic force microscopy (AFM) in order to understand how it influences the mechanical and surface properties. Our results show that introduction of zwitterionic groups into polyurethane can markedly increase the degree of micro-phase separation between the hard and soft segments of the PU chains since the incorporated zwitterionic group leads to more hydrogen bonding and polar interactions, making the hard components to be more thermodynamically incompatible with the soft segments. As the content of the incorporated zwitterionic content increases, the ordered structure in PU chains is reduced, and the micro-phase separation degree is increased. Therefore, the tensile strength and elongation at break of the iNPU films are significantly improved. Dynamic mechanical thermal analysis (DMTA) results further indicate that the Tg of the iNPU coatings decreases, and the deformability greatly increases at a higher content of zwitterionic group. Water contact angle (WCA) measurements reveal the improved surface wetting property due to the presence of zwitterionic group. The antibacterial testing shows that the iNPU coated leather surfaces exhibit reasonably good anti-mold adhesion performance, although the iNPU films do not show apparent contact-killing antibacterial property against E. coli and S. aureus. The present zwitterionic polyurethane is thus can be potentially used as antimicrobial adhesive leather coating materials.

Marine biofouling is one of the most challenging problems today. Silicone polymer based coatings with a low surface energy and elastic modulus can effectively inhibit or release biofouling. However, their non-repairable properties and poor antifouling ability under static conditions limit their applications. Here, we report a self-repairing coating consisting of poly(dimethylsiloxane) based polyurea (PDMS-PUa) and a small amount of organic antifoulant (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) (DCOIT). The coating can completely recover its mechanical properties after damage either in air or artificial seawater at room temperature. Such recovery can be accelerated at a higher temperature. Moreover, the release rate of DCOIT is almost constant and can be regulated by its concentration. Six-month marine field tests demonstrate that the system has a good antifouling/fouling release performance even under static conditions.

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 %.

We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.Keywords: antibiofouling; degradation; hydrolysis; poly(triisopropylsilyl acrylate); poly(ε-caprolactone); polyurethane;

Biodegradable polyurethane with N-(2,4,6-trichlorophenyl)maleimide (TCPM) pendant groups has been prepared via a combination of a thiol–ene click reaction and a condensation reaction. The TCPM moieties acting as antifoulants are released as the polyurethane degrades in the marine environment. The biodegradation and hydrolyzation of the polyurethane were investigated by use of quartz crystal microbalance with dissipation (QCM-D) and hydrolysis experiments. It shows both the enzymatic degradation rate and the hydrolyzation rate decrease with TCPM content, which facilitates increasing the duration of the polyurethane. Marine field tests reveal that the polyurethane has good antifouling ability since the degradation leads to a self-renewal surface and the release of the antifoulants is controlled.

We have developed a novel approach to introduce zwitterions into polyurethane for the preparation of antibiofouling coating. First, the thiol–ene click reaction between 2-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-mercapto-1,2-propanediol (TPG) is used to synthesize dihydroxy-terminated DMAEMA (DMA(OH)2) under UV catalysis. The product has been proved by gel permeation chromatography (GPC), Fourier transform infrared spectrum (FT-IR), proton nuclear magnetic resonance (1H NMR), and high resolution mass spectrometry (HRMS). DMA(OH)2 is then incorporated into polyurethane as side groups by polyaddition with diisocyanate and further reacts with 1,3-propane sultone to obtain the zwitterionic polyurethanes. The presence of sulfobetaine zwitterions side groups has been demonstrated by FT-IR and X-ray photoelectron spectroscopy (XPS). Thermal analysis indicates that the thermal stability is decreased with the increasing content of zwitterionions. The antibiofouling property of polyurethanes has been investigated by the measurement of adsorption of fibrinogen, bovine serum albumin (BSA), and lysozyme on the polyurethanes surface using quartz crystal microbalance with dissipation (QCM-D). The results show that the polyurethane coatings exhibit effective nonspecific protein resistance at higher content of zwitterionic side groups.

Marine biofouling is one of the most challenging problems today. Silicone polymer based coatings with a low surface energy and elastic modulus can effectively inhibit or release biofouling. However, their non-repairable properties and poor antifouling ability under static conditions limit their applications. Here, we report a self-repairing coating consisting of poly(dimethylsiloxane) based polyurea (PDMS-PUa) and a small amount of organic antifoulant (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) (DCOIT). The coating can completely recover its mechanical properties after damage either in air or artificial seawater at room temperature. Such recovery can be accelerated at a higher temperature. Moreover, the release rate of DCOIT is almost constant and can be regulated by its concentration. Six-month marine field tests demonstrate that the system has a good antifouling/fouling release performance even under static conditions.