Interrupting marine fouling with active buffered coatings

Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta.

Fabrication of Stable Liquid-like Wetting Buckled Surfaces as Bioinspired Antibiofouling Coatings by Using Silicon-Containing Block Copolymers

Inspired by animals with a slippery epidermis, durable slippery antibiofouling coatings with liquid-like wetting buckled surfaces are successfully constructed in this study by combining dynamic-interfacial-release-induced buckling with self-assembled silicon-containing diblock copolymer (diBCP). The core diBCP material is polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS). Because silicon-containing polymers with intrinsic characters of low surface energy, they easily flow over and cover a surface after it has undergone controlled thermal treatment, generating a slippery wetting layer on which can eliminate polar interactions with biomolecules. Additionally, microbuckled patterns result in curved surfaces, which offer fewer points at which organisms can attach to the surface. Different from traditional slippery liquid-infused porous surfaces, the proposed liquid-like PDMS wetting layer, chemically bonded with PS, is stable and slippery but does not flow away. PS-b-PDMS diBCPs with various PDMS volume fractions are studied to compare the influence of PDMS segment length on antibiofouling performance. The surface characteristics of the diBCPs─ease of processing, transparency, and antibiofouling, anti-icing, and self-cleaning abilities─are examined under various conditions. Being able to fabricate ecofriendly silicon-based lubricant layers without needing to use fluorinated compounds and costly material precursors is an advantage in industrial practice.

Surface Reconstruction of Silicone-Based Amphiphilic Polymers for Mitigating Marine Biofouling

Poly(dimethylsiloxane) (PDMS) coatings are considered to be environmentally friendly antifouling coatings. However, the presence of hydrophobic surfaces can enhance the adhesion rate of proteins, bacteria and microalgae, posing a challenge for biofouling removal. In this study, hydrophilic polymer chains were synthesised from methyl methacrylate (MMA), Poly(ethylene glycol) methyl ether methacrylate (PEG-MA) and 3-(trimethoxysilyl) propyl methacrylate (TPMA). The crosslinking reaction between TPMA and PDMS results in the formation of a silicone-based amphiphilic co-network with surface reconstruction properties. The hydrophilic and hydrophobic domains are covalently bonded by condensation reactions, while the hydrophilic polymers migrate under water to induce surface reconstruction and form hydrogen bonds with water molecules to form a dense hydrated layer. This design effectively mitigates the adhesion of proteins, bacteria, algae and other marine organisms to the coating. The antifouling performance of the coatings was evaluated by assessing their adhesion rates to proteins (BSA-FITC), bacteria (B. subtilis and P. ruthenica) and algae (P. tricornutum). The results show that the amphiphilic co-network coating (e.g., P-AM-15) exhibits excellent antifouling properties against protein, bacterial and microalgal fouling. Furthermore, an overall assessment of its antifouling performance and stability was conducted in the East China Sea from 16 May to 12 September 2023, which showed that this silicon-based amphiphilic co-network coating remained intact with almost no marine organisms adhering to it. This study provides a novel approach for the development of high-performance silicone-based antifouling coatings.

Controlling Anti-Penetration Performance by Post-Grafting of Fluorinated Alkyl Chains onto Polystyrene-block-poly(vinyl methyl siloxane)

Polydimethylsiloxane (PDMS) has been widely used as a surface coating material, which has been reported to possess dynamic omniphobicity to a wide range of both polar and nonpolar solvents due to its high segmental flexibility and mobility. However, such high flexibility and mobility also enable penetration of small molecules into PDMS coatings, which alter the chemical and physical properties of the coating layers. To improve the anti-penetration properties of PDMS, a series of fluorinated alkyl segments are grafted to a diblock copolymer of polystyrene-block-poly(vinyl methyl siloxane) (PS-b-PVMS) using thiol-ene click reactions. This article reports the chemical characterization of these model fluorosilicone block copolymers and uses fluorescence measurements to investigate the dye penetration characteristics of polymer thin films. The introduction of longer fluorinated alkyl chains can gradually increase the anti-penetration properties as the time to reach the maximum fluorescence intensity (tpeak) gradually increases from 11 s of PS-b-PVMS to more than 1000 s of PS-b-P(n-C6F13-VMS). The improvement of anti-penetration properties is attributed to stronger inter-/intrachain interactions, phase segregation of ordered fluorinated side chains, and enhanced hydrophobicity caused by the grafting of fluorinated alkyl chains.

Silicone-modified polyurea-interpenetrating polymer network fouling release coatings with excellent wear resistance property tailored to regulations

The invasion of alien species via marine organisms attaching to the surfaces of ship hulls is a growing problem. A number of countries have introduced corresponding regulations to combat ship biofouling. One effective way to solve this problem is to apply a fouling release coating with excellent wear resistance. In this study, a silicone-modified polyaspartic ester polyurea was synthesized by a simultaneous crosslinking polymerization. Polyaspartic ester polyurea is employed to form a tightly cross-linked network with excellent toughness and outstanding adhesion, while polydimethylsiloxane is used to form a relatively soft cross-linked network with low surface energy and surface elasticity modulus. Polyurea and silicone molecular chain lock onto each other to form interpenetrating polymer network (IPN) through their respective polymerization systems and cross-linking processes. The synergy between silicone and polyurea provides excellent mechanical properties as well as fouling release performance through the locking mechanism. This study provides a promising and universal strategy for the development of fouling release coatings with excellent wear resistance.

Antioxidant N-acetylcysteine removing ROS: an antifouling strategy inspired by mussels

Marine biofouling is a thorny issue that causes serious economic losses and adverse ecological impacts on marine ecosystems. Effective and promising antifouling strategies such as surface hydration, flow shear force, and lubricant injection have been developed to address this challenge. However, for the complex marine environment, they still appear inadequate. Mussels are a common fouling organism with strong surface adhesion ability. However, when hypoxia and the oxidative cross-linking reaction of 3,4-dihydroxy phenyl-L-alanine (DOPA) in the structure of adhesion proteins are disrupted, their adhesion ability will be greatly reduced. Inspired by this, we developed an effective antifouling strategy based on reactive oxygen species (ROS) scavenging using N-acetylcysteine (NAC) and evaluated its performance. As a ROS scavenger interfered with the oxidative cross-linking reaction of DOPA in an aqueous solution, the adhesion of DOPA was also affected on the surface of NAC functionalized polyvinyl chloride (PVC) (PVC-NAC). In addition, the colonization level of mussels and the adhesion rate of marine bacteria and benthic diatoms on PVC-NAC were low. The antifouling strategy proposed in this paper was eco-friendly and broad-spectrum, and may provide a new idea for solving marine biofouling and reducing the environmental and economic impacts of fouling organisms.

Prevention of marine biofouling in the aquaculture industry by a coating based on polydimethylsiloxane-chitosan and sodium polyacrylate

In this study, a series of novel hydrophobic/hydrophilic hybrid (HHH) coatings with the feature of preventing the fouling phenomenon was fabricated based on polydimethylsiloxane (PDMS), as matrix and two hydrophilic polymers: chitosan and sodium polyacrylate, as dispersed phases. Antibacterial activity, pseudo-barnacle adhesion strength, surface free energy, water contact angle, and water absorption were performed for all samples. Evaluating field immersion of the samples was performed in the natural seawater. The results showed that the dispersed phase containing PDMS coatings showed simultaneously both of antibacterial activity and foul release behavior. Among the samples, the PCs4 coating containing 4 wt% Cs indicated the lowest pseudo barnacle adhesion strength (0.04 MPa), the lowest surface free energy (18.94 mN/m), the highest water contact angle (116.05°), and the percentage of fouling organisms 9.8 % after 30 days immersion. The HHH coatings can be considered as novel eco-friendly antifouling/foul release coatings for aquaculture applications.

Development of Antifouling Coatings Based on Quaternary Ammonium Compounds through a Multilayer Approach

The development of polymeric materials as antifouling coatings for aquaculture nets is elaborated in the present work. In this context, cross-linked polymeric systems based on quaternary ammonium compounds (immobilized or releasable) prepared under mild aqueous conditions were introduced as a more environmentally friendly methodology for coating nets on a large scale. To optimize the duration of action of the coatings, a multilayer coating method was applied by combining the antimicrobial organo-soluble copolymer poly(cetyltrimethylammonium 4-styrenesulfonate-co-glycidyl methacrylate) [P(SSAmC16-co-GMA20)] as the first layer with either the water-soluble copolymer poly(vinylbenzyl trimethylammonium chloride-co-acrylic acid) [P(VBCTMAM-co-AA20)] or the water-soluble polymers poly(acrylic acid) (PAA) and poly(hexamethylene guanidine), PHMG, as the second layer. The above-mentioned approach, followed by thermal cross-linking of the polymeric coatings, resulted in stable materials with controlled release of the biocidal species. The coated nets were studied in terms of their antifouling efficiency under accelerated biofouling conditions as well as under real conditions in an aquaculture field. Resistance to biofouling after three water-nutrient replenishments was observed under laboratory accelerated biofouling conditions. In addition, at the end of the field test (day 23) the uncoated nets were completely covered by marine contaminants, while the coated nets remained intact over most of their extent.

Dual functionalized brush copolymers as versatile antifouling coatings

Polymer coatings containing both fouling-resistant and fouling-release components have been reported to show synergistic antifouling properties. However, it remains unclear how the polymer composition influences the antifouling performance, particularly regarding foulants of different sizes and biological natures. Herein, we prepare dual functionalized brush copolymers containing fouling-resistant poly(ethylene glycol) (PEG) and fouling-release polydimethylsiloxane (PDMS) and examine their antifouling performances against different biofoulants. We utilize poly(pentafluorophenyl acrylate) (PPFPA) as a reactive precursor polymer and graft amine-functionalized PEG and PDMS side chains to create PPFPA-g-PEG-g-PDMS brush copolymers of systematically varying compositions. The copolymer films spin-coated on silicon wafers exhibit surface heterogeneity that can be correlated well with the bulk composition of the copolymer. When the copolymer-coated surfaces are examined against protein (human serum albumin and bovine serum albumin) adsorption and cell (lung cancer cells and microalgae) adhesion, they are found to perform better than the homopolymers. The enhanced antifouling properties are attributed to the copolymers having a PEG-rich top layer and a PEG/PDMS mixed bottom layer that work synergistically to resist biofoulant attachment. Furthermore, the composition of the best-performing copolymer is different for different foulants, with PPFPA-g-PEG₃₉-g-PDMS₄₆ exhibiting the best antifouling properties against proteins and PPFPA-g-PEG₅₄-g-PDMS₃₀ exhibiting the best antifouling properties against cells. We explain this difference by considering the changes in the length scale of the surface heterogeneity in relation to the foulant sizes.

Nitroxide-Containing Amphiphilic Random Terpolymers for Marine Antifouling and Fouling-Release Coatings

Two types of amphiphilic random terpolymers, poly(ethylene glycol methyl ether methacrylate)-ran-poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate)-ran-poly(polydimethyl siloxane methacrylate) (PEGMEMA-r-PTMA-r-PDMSMA), were synthesized and evaluated for antifouling (AF) and fouling-release (FR) properties using diverse marine fouling organisms. In the first stage of production, the two respective precursor amine terpolymers containing (2,2,6,6-tetramethyl-4-piperidyl methacrylate) units (PEGMEMA-r-PTMPM-r-PDMSMA) were synthesized by atom transfer radical polymerization using various comonomer ratios and two initiators: alkyl halide and fluoroalkyl halide. In the second stage, these were selectively oxidized to introduce nitroxide radical functionalities. Finally, the terpolymers were incorporated into a PDMS host matrix to create coatings. AF and FR properties were examined using the alga Ulva linza, the barnacle Balanus improvisus, and the tubeworm Ficopomatus enigmaticus. The effects of comonomer ratios on surface properties and fouling assay results for each set of coatings are discussed in detail. There were marked differences in the effectiveness of these systems against the different fouling organisms. The terpolymers had distinct advantages over monopolymeric systems across the different organisms, and the nonfluorinated PEG and nitroxide combination was identified as the most effective formulation against B. improvisus and F. enigmaticus.

Computational Design of Antimicrobial Active Surfaces via Automated Bayesian Optimization

Biofilms pose significant problems for engineers in diverse fields, such as marine science, bioenergy, and biomedicine, where effective biofilm control is a long-term goal. The adhesion and surface mechanics of biofilms play crucial roles in generating and removing biofilm. Designing customized nanosurfaces with different surface topologies can alter the adhesive properties to remove biofilms more easily and greatly improve long-term biofilm control. To rapidly design such topologies, we employ individual-based modeling and Bayesian optimization to automate the design process and generate different active surfaces for effective biofilm removal. Our framework successfully generated optimized functional nanosurfaces for improved biofilm removal through applied shear and vibration. Densely distributed short pillar topography is the optimal geometry to prevent biofilm formation. Under fluidic shearing, the optimal topography is to sparsely distribute tall, slim, pillar-like structures. When subjected to either vertical or lateral vibrations, thick trapezoidal cones are found to be optimal. Optimizing the vibrational loading indicates a small vibration magnitude with relatively low frequencies is more efficient in removing biofilm. Our results provide insights into various engineering fields that require surface-mediated biofilm control. Our framework can also be applied to more general materials design and optimization.

Antifouling graphene oxide membranes for oil-water separation via hydrophobic chain engineering

Engineering surface chemistry to precisely control interfacial interactions is crucial for fabricating superior antifouling coatings and separation membranes. Here, we present a hydrophobic chain engineering strategy to regulate membrane surface at a molecular scale. Hydrophilic phytic acid and hydrophobic perfluorocarboxylic acids are sequentially assembled on a graphene oxide membrane to form an amphiphilic surface. The surface energy is reduced by the introduction of the perfluoroalkyl chains while the surface hydration can be tuned by changing the hydrophobic chain length, thus synergistically optimizing both fouling-resistance and fouling-release properties. It is found that the surface hydration capacity changes nonlinearly as the perfluoroalkyl chain length increases from C₄ to C₁₀, reaching the highest at C₆ as a result of the more uniform water orientation as demonstrated by molecular dynamics simulations. The as-prepared membrane exhibits superior antifouling efficacy (flux decline ratio <10%, flux recovery ratio ~100%) even at high permeance (~620 L m^-2 h^-1 bar^-1) for oil-water separation.

Polyethylene Glycol-b-poly(trialkylsilyl methacrylate-co-methyl methacrylate) Hydrolyzable Block Copolymers for Eco-Friendly Self-Polishing Marine Coatings

Hydrolyzable block copolymers consisting of a polyethylene glycol (PEG) first block and a random poly(trialkylsilyl methacrylate (TRSiMA, R = butyl, isopropyl)-co-methyl methacrylate (MMA)) second block were synthesized by RAFT polymerization. Two PEGs with different molar masses (M_n = 750 g/mol (PEG1) and 2200 g/mol (PEG2)) were used as macro-chain transfer agents and the polymerization conditions were set in order to obtain copolymers with a comparable mole content of trialkylsilyl methacrylate (~30 mole%) and two different PEG mole percentages of 10 and 30 mole%. The hydrolysis rates of PEG-b-(TRSiMA-co-MMA) in a THF/basic (pH = 10) water solution were shown to drastically depend on the nature of the trialkylsilyl groups and the mole content of the PEG block. Films of selected copolymers were also found to undergo hydrolysis in artificial seawater (ASW), with tunable erosion kinetics that were modulated by varying the copolymer design. Measurements of the advancing and receding contact angles of water as a function of the immersion time in the ASW confirmed the ability of the copolymer film surfaces to respond to the water environment as a result of two different mechanisms: (i) the hydrolysis of the silylester groups that prevailed in TBSiMA-based copolymers; and (ii) a major surface exposure of hydrophilic PEG chains that was predominant for TPSiMA-based copolymers. AFM analysis revealed that the surface nano-roughness increased upon immersion in ASW. The erosion of copolymer film surfaces resulted in a self-polishing, antifouling behavior against the diatom Navicula salinicola. The amount of settled diatoms depended on the hydrolysis rate of the copolymers.

Biomimetic antimicrobial polymers—Design, characterization, antimicrobial, and novel applications

Biomimetic antimicrobial polymers have been an area of great interest as the need for novel antimicrobial compounds grows due to the development of resistance. These polymers were designed and developed to mimic naturally occurring antimicrobial peptides in both physicochemical composition and mechanism of action. These antimicrobial peptide mimetic polymers have been extensively investigated using chemical, biophysical, microbiological, and computational approaches to gain a deeper understanding of the molecular interactions that drive function. These studies have helped inform SARs, mechanism of action, and general physicochemical factors that influence the activity and properties of antimicrobial polymers. However, there are still lingering questions in this field regarding 3D structural patterning, bioavailability, and applicability to alternative targets. In this review, we present a perspective on the development and characterization of several antimicrobial polymers and discuss novel applications of these molecules emerging in the field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

The Use of 3D Optical Coherence Tomography to Analyze the Architecture of Cyanobacterial Biofilms Formed on a Carbon Nanotube Composite

The development of environmentally friendly antifouling strategies for marine applications is of paramount importance, and the fabrication of innovative nanocomposite coatings is a promising approach. Moreover, since Optical Coherence Tomography (OCT) is a powerful imaging technique in biofilm science, the improvement of its analytical power is required to better evaluate the biofilm structure under different scenarios. In this study, the effect of carbon nanotube (CNT)-modified surfaces in cyanobacterial biofilm development was assessed over a long-term assay under controlled hydrodynamic conditions. Their impact on the cyanobacterial biofilm architecture was evaluated by novel parameters obtained from three-dimensional (3D) OCT analysis, such as the contour coefficient, total biofilm volume, biovolume, volume of non-connected pores, and the average size of non-connected pores. The results showed that CNTs incorporated into a commercially used epoxy resin (CNT composite) had a higher antifouling effect at the biofilm maturation stage compared to pristine epoxy resin. Along with a delay in biofilm development, a decrease in biofilm wet weight, thickness, and biovolume was also achieved with the CNT composite compared to epoxy resin and glass (control surfaces). Additionally, biofilms developed on the CNT composite were smoother and presented a lower porosity and a strictly packed structure when compared with those formed on the control surfaces. The novel biofilm parameters obtained from 3D OCT imaging are extremely important when evaluating the biofilm architecture and behavior under different scenarios beyond marine applications.

Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices

This review summarizes recent research on the design of polymer material systems based on biomimetic concepts and reports on the medical devices that implement these systems. Biomolecules such as proteins, nucleic acids, and phospholipids, present in living organisms, play important roles in biological activities. These molecules are characterized by heterogenic nature with hydrophilicity and hydrophobicity, and a balance of positive and negative charges, which provide unique reaction fields, interfaces, and functionality. Incorporating these molecules into artificial systems is expected to advance material science considerably. This approach to material design is exceptionally practical for medical devices that are in contact with living organisms. Here, it is focused on zwitterionic polymers with intramolecularly balanced charges and introduce examples of their applications in medical devices. Their unique properties make these polymers potential surface modification materials to enhance the performance and safety of conventional medical devices. This review discusses these devices; moreover, new surface technologies have been summarized for developing human-friendly medical devices using zwitterionic polymers in the cardiovascular, cerebrovascular, orthopedic, and ophthalmology fields.

Studying the Effect of Pre-Polymer Composition and Incorporation of Surface-Modifying Amphiphilic Additives on the Fouling-Release Performance of Amphiphilic Siloxane-Polyurethane Coatings

Combining amphiphilic fouling-release (FR) coatings with the surface-active nature of amphiphilic additives can improve the antifouling/fouling-release (AF/FR) properties needed to offer broad-spectrum resistance to marine biofoulants. This work is focused on further tuning the amphiphilic character of a previously developed amphiphilic siloxane-polyurethane (SiPU) coating by varying the amount of PDMS and PEG in the base system. Furthermore, surface-modifying amphiphilic additives (SMAAs) were incorporated into these amphiphilic FR SiPU coatings in varying amounts. ATR-FTIR, contact angle and surface energy measurements, and AFM were performed to assess changes in surface composition, wettability, and morphology. AF/FR properties were evaluated using laboratory biological assays involving Cellulophaga lytica, Navicula incerta, Ulva linza, Amphibalanus amphitrite, and Geukensia demissa. The surfaces of these coatings varied significantly upon changes in PDMS and PEG content in the coating matrix, as well as with changes in SMAA incorporation. AF/FR properties were also significantly changed, with formulations containing the highest amounts of SMAA showing very high removal properties compared to other experimental formulations, in some cases better than that of commercial standard FR coatings.

Preparation and Properties of PED-TDI Polyurethane-Modified Silicone Coatings

To explore the influence mechanisms of polyurethane soft segments on modified silicone coatings, a series of modified coatings was prepared by introducing different contents of hydroxypropyl-terminated polydimethylsiloxane (PDMS2200) into the soft segment of polyurethane. ATR-FTIR, NMR, CLSM, AFM, contact angle measurement, the tensile test, bacterial adhesion, and the benthic diatom adhesion test were used to investigate the structure, morphology, roughness, degree of microphase separation, surface energy, tensile properties, and antifouling properties of the modified coatings. The results show that PDMS2200 could aggravate the microphase separation of the modified coatings, increase the surface-free energy, and reduce its elastic modulus; when the microphase separation exceeded a certain degree, increasing PDMS2200 would decrease the tensile properties. The PED-TDI polyurethane-modified silicone coating prepared with the formula of PU-Si17 had the best tensile properties and antifouling properties among all modified coatings.

Squid inspired elastomer marine coating with efficient antifouling strategies: Hydrophilized defensive surface and lower modulus

In antifouling applications for the marine industry, low surface energy coatings entail turbulent water flow to release marine biofouling, which presents a substantial challenge for antifouling in the static situation. The traditional solution is to add environmentally friendly antifouling agents, but it has the problem of exhaustion. Therefore, the low surface energy elastic antifouling coating without antifoulants has high research value. Herein, inspired by soft body and epidermal mucus of squid, the stable polyvinylpyrrolidone (PVP) hydrophilic segments were introduced to modify the polydimethylsiloxane-based polyurethane (PDMS-PU), realizing low surface energy elastomer coatings with hydrophilized defensive surface and reduced elastic modulus (<1.1 MPa). In an aqueous environment, the tailored surface exposed sufficient stable hydrophilic segments, exerting excellent antifouling performance, which improved the anti-adsorption effect on biological proteins, bacteria (antibacterial rate 95.24%) and algae (cover rate <3%). The coating exhibited excellent marine antifouling performance within 150 days and also gave a new impetus to developing an eco-friendly and sustainable solution for no-antifoulant marine antifouling applications.

Mechanically Enhanced Self-Stratified Acrylic/Silicone Antifouling Coatings

Great attention has been paid to silicone-based fouling-release coatings (FRCs) in the realm of maritime antifouling due to their highly efficient and eco-friendly properties, but many challenges remain for developing a silicone-based FRC that improves its adhesion performance without reducing the antifouling property. Herein, a non-toxic silicone-based FRC has been developed by integrating acrylic resin (AR) with a silicon resin (PDMS) to spontaneously form a self-stratified AR/PDMS coating. The AR/PDMS antifouling coating still has the same fouling-release performance but improved adhesion strength (from 0.4 to 2.0 MPa) in comparison with pristine PDMS. Moreover, the antifouling coating has proven to be extremely stable in different environments (such as pH, heating, and ultraviolet exposure). The study provides a facile and convenient self-stratified strategy to develop antifouling coatings, contributing to environmentally friendly coatings in marine applications.

Effects of Amphiphilic Polypeptoid Side Chains on Polymer Surface Chemistry and Hydrophilicity

Polymers are commonly used in applications that require long-term exposure to water and aqueous mixtures, serving as water purification membranes, marine antifouling coatings, and medical implants, among many other applications. Because polymer surfaces restructure in response to the surrounding environment, in situ characterization is crucial for providing an accurate understanding of the surface chemistry under conditions of use. To investigate the effects of surface-active side chains on polymer surface chemistry and resultant interactions with interfacial water (i.e., water sorption), we present synchrotron ambient pressure X-ray photoelectron spectroscopy (APXPS) studies performed on poly(ethylene oxide) (PEO)- and poly(dimethylsiloxane) (PDMS)-based polymer surfaces modified with amphiphilic polypeptoid side chains, previously demonstrated to be efficacious in marine fouling prevention and removal. The polymer backbone and environmental conditions were found to affect polypeptoid surface presentation: due to the surface segregation of its fluorinated polypeptoid monomers under vacuum, the PEO-peptoid copolymer showed significant polypeptoid content in both vacuum and hydrated conditions, while the modified PDMS-based copolymer showed increased polypeptoid content only in hydrated conditions due to the hydrophilicity of the ether monomers and polypeptoid backbone. Polypeptoids were found to bind approximately 2.8 water molecules per monomer unit in both copolymers, and the PEO-peptoid surface showed substantial water sorption that suggests a surface with a more diffuse water/polymer interface. This work implies that side chains are ideal for tuning water affinity without altering the base polymer composition, provided that surface-driving groups are present to ensure activity at the interface. These types of systematic modifications will generate novel polymers that maximize bound interfacial water and can deliver surface-active groups to the surface to improve the effectiveness of polymer materials.

Water- and Acid-Sensitive Cu2O@Cu-MOF Nano Sustained-Release Capsules with Superior Antifouling Behaviors

Marine biofouling is one of the technical bottlenecks restricting the development of the global marine economy. Among the commercial self-polishing antifouling coatings, cuprous oxide is an irreplaceable component because of its efficiency and broad-spectrum antibacterial activity. However, one of the biggest obstacles to achieving long-term antifouling is the "initial burst and final decay" of cuprous oxide in the coating. Here, we lock the copper ions by establishing an antifouling unit composed of Cu₂O (core) and Cu-based metal-organic framework (Cu-MOF, shell). Cu-MOF is densely grown in situ on the periphery of Cu₂O by acid proton etching. The shell structure of Cu-MOF can effectively improve the stability of the internal Cu₂O and thus achieve the stable and slow release of copper ions. Furthermore, Cu₂O@Cu-MOF nanocapsules can also achieve active defense by rapid and complete dissolution of Cu₂O@Cu-MOF at local acidic microenvironment (pH ≤ 5) where the adhesion of fouling organisms occurs. Super-resolution fluorescence microscopy is used to explain the sterilization mechanism. Relying on the water- and acid-sensitive properties of Cu-MOF shell, the stable, controlled and efficient release of copper ions has been achieved for the Cu₂O@Cu-MOF nanocapsules in the self-polishing antifouling coatings. Thus, these controlled-release nanocapsules make long-term antifouling promising.

Synthesis and Antifouling Activity Evaluation of Analogs of Bromosphaerol, a Brominated Diterpene Isolated from the Red Alga Sphaerococcus coronopifolius

Marine biofouling is an epibiotic biological process that affects almost any kind of submerged surface, causing globally significant economic problems mainly for the shipping industry and aquaculture companies, and its prevention so far has been associated with adverse environmental effects for non-target organisms. Previously, we have identified bromosphaerol (1), a brominated diterpene isolated from the red alga Sphaerococcus coronopifolius, as a promising agent with significant antifouling activity, exerting strong anti-settlement activity against larvae of Amphibalanus (Balanus) amphitrite and very low toxicity. The significant antifouling activity and low toxicity of bromosphaerol (1) motivated us to explore its chemistry, aiming to optimize its antifouling potential through the preparation of a number of analogs. Following different synthetic routes, we successfully synthesized 15 structural analogs (2–16) of bromosphaerol (1), decorated with different functional groups. The anti-settlement activity (EC₅₀) and the degree of toxicity (LC₅₀) of the bromosphaerol derivatives were evaluated using cyprids and nauplii of the cirriped crustacean A. amphitrite as a model organism. Derivatives 2, 4, and 6–16 showed diverse levels of antifouling activity. Among them, compounds 9 and 13 can be considered as well-performing antifoulants, exerting their activity through a non-toxic mechanism.

Low Fouling Polysulfobetaines with Variable Hydrophobic Content

Amphiphilic polymer coatings combining hydrophilic elements, in particular zwitterionic groups, and hydrophobic elements comprise a promising strategy to decrease biofouling. However, the influence of the content of the hydrophobic component in zwitterionic coatings on the interfacial molecular reorganization dynamics and the anti-fouling performance is not well understood. Therefore, coatings of amphiphilic copolymers of sulfobetaine methacrylate 3-[N-2'-(methacryloyloxy)ethyl-N,N-dimethyl]-ammonio propane-1-sulfonate (SPE) are prepared which contain increasing amounts of hydrophobic n-butyl methacrylate (BMA). Their fouling resistance is compared to that of their homopolymers PSPE and PBMA. The photo-crosslinked coatings form hydrogel films with a hydrophilic surface. Fouling by the proteins fibrinogen and lysozyme as well as by the diatom Navicula perminuta and the green algae Ulva linza is assessed in laboratory assays. While biofouling is strongly reduced by all zwitterionic coatings, the best fouling resistance is obtained for the amphiphilic copolymers. Also in preliminary field tests, the anti-fouling performance of the amphiphilic copolymer films is superior to that of both homopolymers. When the coatings are exposed to a marine environment, the reduced susceptibility to silt incorporation, in particular compared to the most hydrophilic polyzwitterion PSPE, likely contributes to the improved fouling resistance.

De Novo Design of Entropy-Driven Polymers Resistant to Bacterial Attachment via Multicomponent Reactions

Nonbactericidal polymers that prevent bacterial attachment are important for public health, environmental protection, and avoiding the generation of superbugs. Here, inspired by the physical bactericidal process of carbon nanotubes and graphene derivatives, we develop nonbactericidal polymers resistant to bacterial attachment by using multicomponent reactions (MCRs) to introduce molecular "needles" (rigid aliphatic chains) and molecular "razors" (multicomponent structures) into polymer side chains. Computer simulation reveals the occurrence of spontaneous entropy-driven interactions between the bacterial bilayers and the "needles" and "razors" in polymer structures and provides guidance for the optimization of this type of polymers for enhanced resistibility to bacterial attachment. The blending of the optimized polymer with commercially available polyurethane produces a film with remarkably superior stability of the resistance to bacterial adhesion after wear compared with that of commercial mobile phone shells made by the Sharklet technology. This proof-of-concept study explores entropy-driven polymers resistant to bacterial attachment via a combination of MCRs, computer simulation, and polymer chemistry, paving the way for the de novo design of nonbactericidal polymers to prevent bacterial contamination.

Amphiphilic Polyphosphonate Copolymers as New Additives for PDMS-Based Antifouling Coatings

Poly(ethyl ethylene phosphonate)-based methacrylic copolymers containing polysiloxane methacrylate (SiMA) co-units are proposed as surface-active additives as alternative solutions to the more investigated polyzwitterionic and polyethylene glycol counterparts for the fabrication of novel PDMS-based coatings for marine antifouling applications. In particular, the same hydrophobic SiMA macromonomer was copolymerized with a methacrylate carrying a poly(ethyl ethylene phosphonate) (PEtEPMA), a phosphorylcholine (MPC), and a poly(ethylene glycol) (PEGMA) side chain to obtain non-water soluble copolymers with similar mole content of the different hydrophilic units. The hydrolysis of poly(ethyl ethylene phosphonate)-based polymers was also studied in conditions similar to those of the marine environment to investigate their potential as erodible films. Copolymers of the three classes were blended into a condensation cure PDMS matrix in two different loadings (10 and 20 wt%) to prepare the top-coat of three-layer films to be subjected to wettability analysis and bioassays with marine model organisms. Water contact angle measurements showed that all of the films underwent surface reconstruction upon prolonged immersion in water, becoming much more hydrophilic. Interestingly, the extent of surface modification appeared to be affected by the type of hydrophilic units, showing a tendency to increase according to the order PEGMA < MPC < PEtEPMA. Biological tests showed that Ficopomatus enigmaticus release was maximized on the most hydrophilic film containing 10 wt% of the PEtEP-based copolymer. Moreover, coatings with a 10 wt% loading of the copolymer performed better than those containing 20 wt% for the removal of both Ficopomatus and Navicula, independent from the copolymer nature.

Fouling Release Coatings Based on Acrylate-MQ Silicone Copolymers Incorporated with Non-Reactive Phenylmethylsilicone Oil

Copolymers containing MQ silicone and acrylate were synthesized by controlling the additive amount of compositions. Subsequently, fouling release coatings based on the copolymer with the incorporation of non-reactive phenylmethylsilicone oil were prepared. The surface properties of the coating (CAMQ₄₀) were consistent with that of the polydimethylsiloxane (PDMS) elastomer, which ensured good hydrophobicity. Moreover, the seawater volume swelling rate of all prepared coatings was less than 5%, especially for CAMQ₄₀ with only 1.37%. Copolymers enhanced the mechanical properties of the coatings, while the enhancement was proportional to the molar content of structural units from acrylate in the copolymer. More importantly, the adhesion performance between the prepared coatings and substrates indicated that pull-off strength values were more than 1.6 MPa, meaning a high adhesion strength. The phenylmethylsilicone oil leaching observation determined that the oil leaching efficiency increased with the increase in the structural unit’s molar content from MQ silicone in the copolymer, which was mainly owing to the decrease in compatibility between oil and the cured coating, as well as the decrease in mechanical properties. High oil leaching efficiency could make up for the decrease in the biofouling removal rate due to the enhancement of the elastic modulus. For CAMQ₄₀, it had an excellent antifouling performance at 30 days of exposure time with more than 92% of biofouling removal rate, which was confirmed by biofilm adhesion assay.

Innovative fouling-resistant materials for industrial heat exchangers: a review

Fouling of heat exchangers (HEs) has become a major concern across the industrial sector. Fouling is an omnipresent phenomenon but is particularly prevalent in the dairy, oil, and energy industries. Reduced energy performance that results from fouling represents significant operating loss in terms of both maintenance and impact on product quality and safety. In most industries, cleaning or replacing HEs are currently the only viable solutions for controlling fouling. This review examines the latest advances in the development of innovative materials and coatings for HEs that could mitigate the need for costly and frequent cleaning and potentially extend their operational life. To better understand the correlation between surface properties and fouling occurrence, we begin by providing an overview of the main mechanisms underlying fouling. We then present selected key strategies, which can differ considerably, for developing antifouling surfaces and conclude by discussing the current trends in the search for ideal materials for a range of applications. In our presentation of all these aspects, emphasis is given wherever possible to the potential transfer of these innovative surfaces from the laboratory to the three industries most concerned by HE fouling problems: food, petrochemicals, and energy production.

A critical review on surface modifications mitigating dairy fouling

Thermal treatments performed in food processing industries generate fouling. This fouling deposit impairs heat transfer mechanism by creating a thermal resistance, thus leading to regular shutdown of the processes. Therefore, periodic and harsh cleaning-in-place (CIP) procedures are implemented. This CIP involves the use of chemicals and high amounts of water, thus increasing environmental burden. It has been estimated that 80% of production costs are owed to dairy fouling deposit. Since the 1970s, different types of surface modifications have been performed either to prevent fouling deposition (anti-fouling) or to facilitate removal (fouling-release). This review points out the impacts of surface modification on type A dairy fouling and on cleaning behaviors under batch and continuous flow conditions. Both types of anti-fouling and fouling-release coatings are reported as well as the different techniques used to modify stainless steel surface. Finally, methods for testing and characterising the effectiveness of coatings in mitigating dairy fouling are discussed.

Biomimetic surface coatings for marine antifouling: Natural antifoulants, synthetic polymers and surface microtopography

Marine biofouling is a ubiquitous problem that accompanies human marine activities and marine industries. It exerts detrimental impacts on the economy, environment, ecology, and safety. Traditionally, mainstream approaches utilize metal ions to prevent biological contamination, but this also leads to environmental pollution and damage to the ecosystem. Efficient and environmentally friendly coatings are urgently needed to prevent marine devices from biofouling. Since nature is always the best teacher for humans, it offers us delightful thoughts on the research and development of high-efficiency, broad-spectrum and eco-friendly antifouling coatings. In this work, we focus on the research frontier of marine antifouling coatings from a bionic perspective. Enlightened by three distinctive dimensions of bionics: chemical molecule bionic, physiological mechanism bionic, and physical structure bionic, the research status of three main bioinspired strategies, which are natural antifoulants, bioinspired polymeric antifouling coatings, and biomimetic surface microtopographies, respectively, are demonstrated. The antifouling mechanisms are further interpreted based on biomimetic comprehension. The main fabrication methods and antifouling performances of these coatings are presented along with their advantages and drawbacks. Finally, the challenges are summarized, and future research prospects are proposed. It is believed that biomimetic antifouling strategies will contribute to the development of nontoxic antifouling techniques with exceptional repellency and stability.

New Light in Polymer Science: Photoinduced Reversible Addition-Fragmentation Chain Transfer Polymerization (PET-RAFT) as Innovative Strategy for the Synthesis of Advanced Materials

Photochemistry has attracted great interest in the last decades in the field of polymer and material science for the synthesis of innovative materials. The merging of photochemistry and reversible-deactivation radical polymerizations (RDRP) provides good reaction control and can simplify elaborate reaction protocols. These advantages open the doors to multidisciplinary fields going from composite materials to bio-applications. Photoinduced Electron/Energy Transfer Reversible Addition-Fragmentation Chain-Transfer (PET-RAFT) polymerization, proposed for the first time in 2014, presents significant advantages compared to other photochemical techniques in terms of applicability, cost, and sustainability. This review has the aim of providing to the readers the basic knowledge of PET-RAFT polymerization and explores the new possibilities that this innovative technique offers in terms of industrial applications, new materials production, and green conditions.

Sulfobetaine Methacrylate Polymers of Unconventional Polyzwitterion Architecture and Their Antifouling Properties

Combining high hydrophilicity with charge neutrality, polyzwitterions are intensely explored for their high biocompatibility and low-fouling properties. Recent reports indicated that in addition to charge neutrality, the zwitterion's segmental dipole orientation is an important factor for interacting with the environment. Accordingly, a series of polysulfobetaines with a novel architecture was designed, in which the cationic and anionic groups of the zwitterionic moiety are placed at equal distances from the backbone. They were investigated by in vitro biofouling assays, covering proteins of different charges and model marine organisms. All polyzwitterion coatings reduced the fouling effectively compared to model polymer surfaces of poly(butyl methacrylate), with a nearly equally good performance as the reference polybetaine poly(3-(N-(2-(methacryloyloxy)ethyl)-N,N-dimethylammonio)propanesulfonate). The specific fouling resistance depended on the detailed chemical structure of the polyzwitterions. Still, while clearly affecting the performance, the precise dipole orientation of the sulfobetaine group in the polyzwitterions seems overall to be only of secondary importance for their antifouling behavior.

Effectiveness and Mechanisms of Recoverable Magnetic Nanoparticles on Mitigating Golden Mussel Biofouling

Mussel biofouling has become a problem in aquatic ecosystems, causing significant ecological impact and huge economic loss globally. Although several strategies have been proposed and tested, efficient and environment-friendly antifouling methods are still scarce. Here, we investigated the effects of recoverable magnetic ferroferric oxide nanoparticles (Fe₃O₄-NPs) with different sizes (10 and 100 nm), coatings (polyethylene glycol and polylysine), and concentrations (0.01 and 0.1 mg/L) on byssus adhesion-mediated biofouling by the notorious golden mussel Limnoperna fortunei. The results showed that magnetic Fe₃O₄-NPs, especially negatively charged polyethylene glycol-coated Fe₃O₄-NPs, size- and concentration-dependently reduced the byssus production, performance (breaking force and failure location), and adhesion rate. Further investigations on mechanisms showed that the down-regulation of foot protein 2 (Lffp-2) and energy-related metabolic pathways inhibited byssus production. The declined gene expression level and metal-binding ability of Lffp-2 significantly affected foot protein interactions, further reducing the plaque size and byssus performance. In addition, the change in the water redox state likely reduced byssus performance by preventing the interface interactions between the substrate and foot proteins. Our results confirm the effectiveness and underlying mechanisms of magnetic Fe₃O₄-NPs on mitigating L. fortunei biofouling, thus providing a reference for developing efficient and environment-friendly antifouling strategies against fouling mussels.

Discontinuous Molecular Dynamics Simulations of Biomolecule Interfacial Behavior: Study of Ovispirin-1 Adsorption on a Graphene Surface

Fundamental understanding of biomolecular interfacial behavior, such as protein adsorption at the microscopic scale, is critical to broad applications in biomaterials, nanomedicine, and nanoparticle-based biosensing techniques. The goal of achieving both computational efficiency and accuracy presents a major challenge for simulation studies at both atomistic and molecular scales. In this work, we developed a unique, accurate, high-throughput simulation method which, by integrating discontinuous molecular dynamics (DMD) simulations with the Go-like protein-surface interaction model, not only solves the dynamics efficiently, but also describes precisely the protein intramolecular and intermolecular interactions at the atomistic scale and the protein-surface interactions at the coarse-grained scale. Using our simulation method and in-house developed software, we performed a systematic study of α-helical ovispirin-1 peptide adsorption on a graphene surface, and our study focused on the effect of surface hydrophobic interactions and π-π stacking on protein adsorption. Our DMD simulations were consistent with full-atom molecular dynamics simulations and showed that a single ovispirin-1 peptide lay down on the flat graphene surface with randomized secondary structure due to strong protein-surface interactions. Peptide aggregates were formed with an internal hydrophobic core driven by strong interactions of hydrophobic residues in the bulk environment. However, upon adsorption, the hydrophobic graphene surface can break the hydrophobic core by denaturing individual peptide structures, leading to disassembling the aggregate structure and further randomizing the ovispirin-1 peptide's secondary structures.

Effect of N-(2-Aminoethyl)-3-Aminopropyltrimethoxysilane on the Adhesion of the Modified Silicone Tie-Coating to Epoxy Primer

In this work, modified silicone tie-paints were prepared in a simple way for securing adhesion between the epoxy anticorrosive primer and silicone fouling release coating. Hydroxy-terminated polydimethylsiloxane (PDMS) mixture containing fillers and accessory ingredient was prepared as base component. N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (DAMO) was mechanically mixed with other functional additives as curing component. ATR-FTIR, XPS, SEM and tensile tests were used to investigate the chemical structure, morphology and mechanical properties of the tie-coatings. It was focused on the effect of the DAMO content on the adhesion of the tie-coating to epoxy primer. Peel off and shear tests were carried out to evaluate the adhesion. The results showed that introducing DAMO can significantly improve the properties of the tie-coating. The adhesion between the tie-coating and the epoxy primer increases with the increase of DAMO content, but the excessive DAMO content will decrease the fracture strength of the tie-coating and decrease the quality of the coating. When the DAMO content in tie-coating is 1.97 wt.%, the tie-coating performs excellent in the interlaminar adhesion, shear strength and mechanical properties.

Self-healing, highly elastic and amphiphilic silicone-based polyurethane for antifouling coatings

Amphiphilic silicone-based polyurethane coatings with room temperature self-healing ability, high elasticity, excellent fouling release and fouling resistance have been reported.

Antifouling Technology Trends in Marine Environmental Protection

Marine fouling is a worldwide problem, which is harmful to the global marine ecological environment and economic benefits. The traditional antifouling strategy usually uses toxic antifouling agents, which gradually exposes a serious environmental problem. Therefore, green, long-term, broad-spectrum and eco-friendly antifouling technologies have been the main target of engineers and researchers. In recent years, many eco-friendly antifouling technologies with broad application prospects have been developed based on the low toxicity and non-toxicity antifouling agents and materials. In this review, contemporary eco-friendly antifouling technologies and materials are summarized into bionic antifouling and non-bionic antifouling strategies (2000-2020). Non-bionic antifouling technologies mainly include protein resistant polymers, antifoulant releasing coatings, foul release coatings, conductive antifouling coatings and photodynamic antifouling technology. Bionic antifouling technologies mainly include the simulated shark skin, whale skin, dolphin skin, coral tentacles, lotus leaves and other biology structures. Brief future research directions and challenges are also discussed in the end, and we expect that this review would boost the development of marine antifouling technologies.

Gut microbiota-mediated tributyltin-induced metabolic disorder in rats

Tributyltin (TBT), an environmental pollutant widely used in antifouling coatings, can cause multiple-organ toxicity and gut microbiome dysbiosis in organisms, and can even cause changes in the host metabolomic profiles. However, little is known about the underlying effects and links of TBT-induced metabolic changes and gut microbiome dysbiosis. In this study, rats were exposed to TBT at a dose of 100 μg kg^-1 body weight (BW) for 38 days, followed by multi-omics analysis, including microbiome, metabolomics, and metallomics. Results showed that TBT exposure reduced rat weight gain and decreased the serum triglyceride (TG) level. Metabolic analysis revealed that TBT fluctuated linoleic acid metabolism and glycerophospholipid metabolism in the liver; the tricarboxylic acid cycle (TCA cycle), nicotinate and nicotinamide metabolism, and arachidonic acid metabolism in serum; glycine, serine, and threonine metabolism, the one carbon pool by folate, nicotinate, and nicotinamide metabolism; and tryptophan metabolism in feces. Furthermore, TBT treatment dictated liver inflammation due to enhancing COX-2 expression by activating protein kinase R-like ER kinase (PERK) and C/EBP homologous protein (CHOP) to induce endoplasmic reticulum (ER) stress instead of stimulating arachidonic acid metabolism. Meanwhile, alteration of the intestinal flora [Acetivibrio]_ethanolgignens_group, Acetatifactor, Eisenbergiella, Lachnospiraceae_UCG-010, Enterococcus, Anaerovorax, and Bilophila under TBT exposure were found to be involved in further mediating liver inflammation, causing lipid metabolism abnormalities, such as TG, linoleic acid, and glycerophospholipids, and interfering with the energy supply process. Among these, [Acetivibrio]_ethanolgignens_group, Enterococcus, and Bilophila could be considered as potential biomarkers for TBT exposure based on receiver operator characteristic (ROC) curve analysis.

Protein Corona on Gold Nanoparticles Studied with Coarse-Grained Simulations

Understanding protein corona formation in an aqueous environment at the molecular and atomistic levels is critical to applications such as biomolecule-detection and drug delivery. In this work, we employed mesoscopic coarse-grained simulations to study ovispirin-1 and lysozyme protein coronas on bare gold nanoparticles. Our study showed that protein corona formation is governed by protein-surface and protein-protein interactions, as well as the surface hydrophobic effect. The corona structure was found to be dependent on protein types and the size of nanoparticles. Ovispirin proteins form homogeneous single-layered adsorption in comparison with the lysozyme's inhomogeneous multilayered aggregates on gold NP surfaces. The decrease in nanoparticle size leads to more angular degrees of freedom for protein adsorption orientation. Subsequent atomistic molecular dynamics simulations further demonstrate the loss of secondary structure of ovispirin upon adsorption and the heterogeneity of its local structure.

New amphiphilic copolymers for PDMS-based nanocomposite films with long-term marine antifouling performance

Amphiphilic methacrylate copolymers (Si-co-EF) containing polysiloxane (Si) and mixed poly(oxyethylene)-perfluorohexyl (EF) side chains were synthesized with different compositions and used together with polysiloxane-functionalized nanoparticles as additives of condensation cured nanocomposite poly(siloxane) films. The mechanical properties of the nanocomposite films were consistent with the elastomeric behavior of the poly(siloxane) matrix without significant detriment from either the copolymer or the nanoparticles. Films were found to be markedly hydrophobic and liphophobic, with both properties being maximized at an intermediate content of EF units. The high enrichment in fluorine at the film surface was proven by angle-resolved X-ray photoelectron spectroscopy (AR-XPS). Long-term marine antifouling performance was evaluated in field immersion trials of test panels for up to 10 months of immersion. Both nanoparticles and amphiphilic copolymer were found to be highly effective in reducing the colonization of foulants, especially hard macrofoulants, when compared with control panels. Lowest percentage of surface coverage was 20% after 10 months of immersion (films with 4 wt% copolymer and 0.5 wt% nanoparticles), which was further decreased to less than 10% after exposure to a water jet for 10 s. The enhanced antifouling properties of coatings containing both nanoparticles and copolymer were confirmed by laboratory assays against the polychaete Ficopomatus enigmaticus and the diatom Navicula salinicola.

Degradable hyaluronic acid/chitosan polyelectrolyte multilayers with marine fouling-release properties

Polysaccharide multilayers consisting of hyaluronic acid and chitosan were prepared by layer-by-layer assembly. To be used in seawater, the multilayers were crosslinked to a different degree using thermal or chemical methods. ATR-FTIR revealed different amide densities as a result of the crosslinking conditions. AFM showed that the crosslinking affected the roughness and swelling behavior of the coatings. The stability and degradability of the multilayers in aqueous environments were monitored with spectroscopic ellipsometry. The resistance of the coatings against non-specific protein adsorption was characterized by SPR spectroscopy. Settlement assays using Ulva linza zoospores and removal assays using the diatom Navicula incerta showed that the slowly degradable coatings were less prone to fouling than the strongly crosslinked ones. Thus, the coatings were a suitable model system to show that crosslinking the multilayers under mild conditions and equipping the coatings with controlled degradation rates enhances their antifouling and fouling-release properties against marine fouling organisms.