Application of marine biotechnology in the production of natural biocides for testing on environmentally innocuous antifouling coatings

The widely recognized biofouling phenomenon has many negative consequences for artificial structures that are in contact with seawater in the form of structural defects and additional expenses for maritime companies due to cleaning and prevention processes. After having analyzed the serious environmental problems caused by an indiscriminate use of highly toxic biocides coming from organic derivatives of tin compounds and the uncontrolled emissions of volatile organic compounds (VOC) to the atmosphere, the evolving technology of antifouling paintings (further mandated by current environmental standards) aims to develop environmentally innocuous water-based coverings in which extracts of the very same marine world are used as biocide compounds. Water-based coatings are being developed that use low-toxic elements and natural biocides, where bacteria is isolated from surfaces immersed in the marine environment, creating a promising source of natural antifouling compounds. The result is a new environmentally friendly antifouling coating that is able to mitigate the problem of biofouling without affecting the surrounding medium, and which may be applied on any artificial structure in contact with seawater. An erratum to this article can be found at     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment

Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose–lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.     

Cupric tannate: A low copper content antifouling pigment

Fouling organisms attached to man-made surfaces submerged in seawater constitute a major worldwide technical and economical problem. Protection against biofouling is essential for efficient service of boats and ships. Due to recent and imminent restrictions of the use of traditional toxic antifouling paints, there is a growing need for new alternative compounds that ensure a good performance without polluting the marine ecosystem.

The aim of this work is to develop a new antifouling formulation using compounds of natural origin, i.e. tannates, in combination with a minimum concentration of a known bioactive pigment, i.e. copper.

Laboratory assays have shown that cupric tannate has a narcotic effect on biofouling larvae. In the field, after 12 months of immersion in Mar del Plata harbor (Argentine), none of the tested painted panels showed macrofouling organisms. This result was obtained with a large decrease in copper content in the order of 40 times relative to conventional cuprous oxide based paints.

Because copper tannate is not lethal at low concentrations, this pigment has an excellent potential as an antifouling agent.     

RP-HPLC optimization of econea by using artificial neural networks and its antifouling performance on the Turkish coastline

Coverage of artificial surfaces within seawater by fouling organisms is defined as biofouling. Although biofouling is a natural process, it has some disadvantages for shipping industry such as increased fuel consumption, and CO₂ emission. Therefore, the ships' hull must be covered by antifouling (AF) or fouling release type coatings to overcome biofouling. In general, the so-called self-polishing AF paints contain biocides for preventing fouling organisms. Their concentrations and release rates from AF coatings are of great importance and they definitely affect both quality and cost of the coating. In the present study, we aimed at applying a new robust method. In this method, we used a model biocide, i.e., econea, to obtain its RP-HPLC optimization through artificial neural networks (ANN) and to see its antifouling performance. Column temperature, mobile phase ratio, flow rate, concentration and wavelength as input parameters and retention time as an output parameter were used in the ANN modeling. In conclusion, the R&D groups in AF paint industry may use RP-HPLC method supported with ANN modeling in further studies.     

Seawater-soluble pigments and their potential use in self-polishing antifouling paints: simulation-based screening tool

This work concerns the on-going development of efficient and environmentally friendly antifouling paints for biofouling control on large ocean-going ships. It is illustrated how a detailed mathematical model for a self-polishing antifouling paint exposed to seawater can be used as a product engineering tool to obtain a quick estimate of the paint behaviour that a given seawater-soluble pigment will provide. In the present context, “pigment” refers to relevant particulate solids of organic-, inorganic-, or biological nature. Simulations performed at 15 and 30 °C suggest that pigment solubility and seawater diffusivity of dissolved pigment species have a significant influence on the polishing and leaching behaviour of a typical self-polishing paint system. The pigment size distribution, on the other hand, only has a minor influence on the paint–seawater interaction. Simulations also indicate that only compounds which are effective against biofouling at very low seawater concentrations are useful as active antifouling paint ingredients. The need for model verification and exploration of practical issues, subsequent a given pigment has been found of interest, is discussed. The model approach is of relevance in the search for novel antifouling paints and for the development of accelerated test methods.     

有机硅和氟树脂在海洋防污涂料中的应用研究进展

海洋生物污损是一个世界性难题,随着人们环境保护意识的增强,发展有效的环保型海洋防污体系成为该领域最重要的研究方向。有机硅/氟基海洋防污涂料具有环保无毒的特点,是目前的研究热点之一。文章概述了有机硅和氟低表面能防污涂料的研究进展,重点介绍了基于仿生原理的有机硅/氟污损释放型防污涂料,论述了材料表面特性包括物理特性、化学特性、结构特征等对生物附着的影响,介绍了两亲性添加剂改性的有机硅防污涂料的开发,展望了污损释放型防污涂料未来的发展方向。     

Techniques for the measurement of natural product incorporation into an antifouling coating

The control of biofouling can be achieved by a variety of methods but for an open system, such as a ship's hull, a protective paint coating is the most adopted method. The incorporation of a natural product extract directly into a coating has received little previous attention. This study has investigated a combination of the antifouling compound (a natural product extract) and the delivery system (control depletion polymer) investigated together. It was necessary to investigate the natural product incorporation into a coating and finally assess the antifouling system including the primer layers in the natural marine environment. Natural products must first be practical as antifoulants to be developed further into a functional system by their incorporation into surfaces or coatings. To demonstrate this, the natural product under investigation was homogenised into a blank proprietary antifouling paint system binder, applied to primed and un-primed ship grade steel and immersed in marine environments. Electrochemical techniques were used to investigate the effects of natural product incorporation into a coating. In addition, optical and scanning electron microscopes were used to assess the physical characteristics of the coating system. The most rigorous test for an antifouling system is a field trial. Field trials were completed at a raft exposure facility, in estuarine dock conditions at the Empress dock, National Oceanography Centre, Southampton, UK.     

Challenges for the Development of New Non-Toxic Antifouling Solutions

Marine biofouling is of major economic concern to all marine industries. The shipping trade is particularly alert to the development of new antifouling (AF) strategies, especially green AF paint as international regulations regarding the environmental impact of the compounds actually incorporated into the formulations are becoming more and more strict. It is also recognised that vessels play an extensive role in invasive species propagation as ballast waters transport potentially threatening larvae. It is then crucial to develop new AF solutions combining advances in marine chemistry and topography, in addition to a knowledge of marine biofoulers, with respect to the marine environment. This review presents the recent research progress made in the field of new non-toxic AF solutions (new microtexturing of surfaces, foul-release coatings, and with a special emphasis on marine natural antifoulants) as well as the perspectives for future research directions.     

Synthesis and antibiofouling properties of novel crosslinkable terpolymers containing semifluoroalkyl substituted aromatic side chains

Synthesis, contact angle analysis, surface properties and biofouling characteristics of novel crosslinkable terpolymers with semifluoroalkyl substituted aromatic side chains have been described. These polymers are targeted for use as coatings to prevent marine biofouling. The marine antifouling properties of these materials were evaluated by laboratory assays employing the fouling diatom Nitzschia and ubiquitous Staphylococcus aureusi. Results indicated that the experimental coatings exhibited better antibiofouling performance than that of a standard Poly(dimethyl siloxane) (PDMS) coating. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

海洋监测仪器防污技术的对比研究

针对海洋监测仪器的防生物附着问题，通过调研筛选出了以防污涂料为主的多种防污材料，并设计不同类型的构件对所选防污材料进行实海防污性能评测，为海洋监测仪器的防生物附着问题提供可供选择的技术方案。     

修饰表面抑制不同物系污垢现状

简要综述了近年来采用表面修饰方法抑制不同物系在换热表面上的污垢形成方面的研究现状,并提出了进一步研究的方向。易结垢物系包括:牛奶等食品类、无机盐类、海水及地热水等;表面修饰方法涉及:溅射、离子植入、真空蒸镀、化学气相沉积、自催化或化学镀、溶胶凝胶、液相沉积、低压电子束和等离子氩弧沉积等。     

环境友好型纳米银海洋防污损涂料研究

开发低毒、无毒的环境友好型抗海洋生物污损涂料的途径主要有两个方面：一是寻找防污高分子材料;二是寻找无毒的防污剂,在不破坏环境的前提下防止生物附着。综述了环境友好型抗海洋生物污损涂料的研究现状,结合纳米银在防污涂料中的应用,探讨了抗海洋生物污损涂料的发展趋势。     

Marine biofouling inhibition by polyurethane conductive coatings used for fishing net

The purpose of the present study is to develop a new conductive coating for application on fishing nets that can be used as an anode, while submersed in the sea, to generate free chlorine which will in turn inhibit marine biofouling. To confirm the durability and viability of this coating, long-term field tests were carried out in the Nanao harbor in Taiwan. Electrical resistivity tests showed that polyurethane resin with carbon black and graphite can demonstrate the lowest resistivity: 0.06 Ωm. This sample also generated optimal quantities of free chlorine, which performs excellent antifouling properties. The use of carbon black in conjunction with graphite did prove to yield greater benefits. A 500-day field test showed that the PU-CG conductive coatings reduced the quantity of marine biofouling attached to the cage by approximately 79%. Furthermore, the chlorine produced was within safe levels, and judged not to pollute the sea. However, this antifouling system still shows durable problems which remain to be considered.     

Development of hybrid antifouling paints

The objectives of this study are to measure the efficiency of a hybrid system for antifouling paint and to observe the influence of the physico-chemical properties of the binder on the antifouling activity. Poly(ɛ-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS) homopolymers are already used as binder for different antifouling strategies. The use of the block copolymer should allow to mix the properties of erosion and hydrophobicity to obtain a more efficient paint with a reduced environmental impact.Paints containing triblock copolymer were immersed in seawater in Lorient harbour to evaluate their antifouling activities. The water absorption, the degradation and the surface properties of the copolymer were measured in distilled water to understand the influence of the binder characteristics in the resulting antifouling properties.The hybrid paints have shown efficiency close to a commercial paint during their immersion in situ in spite of inadequate static conditions of test.     

Marine macrofouling: a review of control technology in the context of an on-line experiment in the turbine condenser water box of Al-Jubail Phase-1 power/MSF plants

The problem of macrofouling has serious implications in the performance of desalination and power plants. Intake structures, screens, seawater piping systems and heat-exchanger tubes are the sites worst affected in the plants, causing an overall decline in plant efficiency at great economic cost. The last half century has witnessed significant advancements in the development ofmacrofouling control technologies. Materials of inherent antifouling properties are widely used in the construction sector. Control technologies available include antifouling paints and coatings, injection of biocides, marine bio-active compounds, materials of inherent antifouling properties, heat treatment, pulse-power devices, UV and nuclear radiation, scrubbing devices, biological control, etc. A literature search carried out during the last few years has yielded about 450 references. This paper presents, in a very concise manner, state-of-the- art macrofouling control technologies pertinent to desalination and power plants in the Kingdom. The paper also discusses the issues of biofouling control in the Al-Jubail plants based on the results of an on-line macrofouling experiment conducted in one of the turbine condensers of Al-Jubail phase-I MSF/power plants.     

High-Throughput Screening of Fouling-Release Properties: An Overview

Marine biofouling of ship hulls has significant cost, performance and environmental implications. Due to environmental concerns associated with traditional antifouling paints that mitigate fouling with the use of biocides, increasing research and development efforts have been made on fouling-release (FR) coatings. FR coatings do not actively deter settlement of marine organisms, but, instead, mitigate biofouling by minimizing the strength of adhesion. Ideally, an FR coating will allow the fouling community to be removed by simply running the vessel at relatively high speed. Traditional methods for characterizing FR properties involve immersion of relatively large samples in the ocean and waiting months for enough fouling to occur to enable reliable measurements to be made. To greatly enhance research and development relative to FR coatings, a combinatorial/high-throughput workflow was developed that includes a suite of FR laboratory assays involving marine bacteria, microalgae, and live, adult barnacles. The novel high-throughput FR measurement systems have been shown to allow for rapid screening of FR characteristics of miniaturized coating samples arranged in an array format.     

Environmentally Benign Fouling-Resistant Marine Coatings: A Review

The undesirable accumulation of marine organisms on any surfaces immersed in seawater is termed as marine fouling. This natural phenomenon contributes a major economic concern for marine industries, e.g. for ships, vessels, oil, wind-turbine sea-platforms, pipelines, water valves and filters by limiting the performances of the devices and materials. In the last decades, several efforts have been employed in the development of efficient antifouling (AF) coatings by following the recent trend in materials science. The current review presents the research and development made in AF strategies for coatings based on two main approaches, detachment of biofoulants or preventing biofoulants attachment.     

Kinetics models for polyacrylamide-graphene oxide composites as antifoulant

Antifouling paints are used to protect the surface against these organisms such as algae, sea squirts, and barnacles. According to previous research, fish and seaweeds do not adhere to submerged surfaces using wet and soft hydrogels. The aim of this study is to investigate the temperature effect on the performance of antifouling composites to develop new useful antifouling composites for shipping sector. In this swelling experiment, the behavior of hydrogels produced from polyacrylamide (PAAm) and graphene oxide (GO) was investigated at different temperatures. Free-radical cross-linking copolymerization formed composite, using acrylamide, ammonium persulfate, N, N′-methylenebisacrylamide (BIS, Merck), and graphene oxide with various contents. The steady-state fluorescence technique was used for studying the swelling of PAAm-GO composites at various temperatures in pure water. When pyranine fluorescence intensity, I was measured, it decreased until swelling equilibrium was achieved. After the swelling experiment was started, the fluorescence emission (I_em) and scattering light intensities, I_sc from different GO content hydrogels were observed by real-time monitoring at various temperatures. Li-Tanaka and Fickian models were used to determine the diffusion coefficients for the swelling experiments in distilled and Marmara Sea Water for 8 and 50 μl of GO content hydrogels, respectively. According to literature, PAAm is utilized as a surface coating material to reduce biofouling, for this reason, this research will show a way to be able to use PAAm inside antifouling paints material for the marine industry.     

Low surface energy self-polishing polymer grafted MWNTs for antibacterial coating and controlled-release property of Cu2O

Marine biofouling had been a headache when engaging in marine activities. The most effective and convenient method for dealing with this problem was to apply antifouling coatings. But now a single anti-fouling system was hard to satisfy the requirement of anti-fouling simultaneously. Therefore, it was particularly important to develop novel multi-system anti-fouling technology. In the work, a novel polymer coatings with polydimethylsiloxane (PDMS) segments in the main chain and hydrolysable side chain was designed and synthesized which showed low surface energy and self-polishing performance, and then we creatively covalently immobilized the polyurethane on the surface of multi-carbon nanotubes (MWNTs) to form multisystem antifouling coating. The results showed that the polymer coating would produce hydrolysable regions in the hydrophobic PDMS segment to endure the polymer coating hydrophobic and hydrolysis properties when contacted with water. In addition, the self-polishing rate and the surface energy could be regulated by varying its copolymerization, and the addition of MWNTs could kill the microorganisms and endowed the polymer coating itself enhanced antibacterial effect. Furthermore, considering the high specific surface area and physicochemical characteristics of MWNTs, it could be combined with antifoulant Cu₂O through a polar or non-polar combination as a carrier to control the release rate of Cu₂O in coatings.