Preparation and properties of crosslinked network coatings based on perfluoropolyether/poly(dimethyl siloxane)/acrylic polyols for marine fouling–release applications

α,ω‐Triethoxysilane terminated poly(dimethyl siloxane) (PDMS) oligomer, α,ω‐triethoxysilane terminated perfluoropolyether (PFPE) oligomer, and acrylic polyols were first synthesized via an addition reaction and free‐radical polymerization. Then, crosslinked network coatings based on PFPE/PDMS/acrylic polyols for marine fouling‐release applications were prepared by a condensation reaction. The structure of the crosslinked network coating was characterized by Fourier transform infrared spectroscopy. The chemical composition of the coating surface was characterized by X‐ray photoelectron spectroscopy. The thermal properties, surface energy, mechanical properties, adhesion, and antiseawater immersion performance of the coatings were systematically studied. The antibiofouling properties of the crosslinked network coating were evaluated by laboratory biofouling assays with the bacteria Escherichia coli and the fouling diatom Navicula. The results from the preliminary study suggested that this crosslinked network coating had good adhesion and promising antifouling properties that were comparable to a silicone standard. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41860.     

Urushiol titanium polymer-based composites coatings for anti-corrosion and antifouling in marine spray splash zones

Seawater is highly corrosive, and the alternating dry and wet environment can cause severe corrosion in metal equipment. Moreover, marine equipment is also seriously affected by marine biofouling. These harsh conditions pose a serious threat to the integrity of marine equipment as well as their associated maritime activities and necessitate the development of effective coatings to minimize damage to the equipment. Urushiol titanium polymer/acrylic resin (UTP/AR) composite materials were developed. Then, marine anti-corrosion and antifouling coatings were prepared from the UTP/AR composite materials using rosin-modified Cu₂O as an antifoulant. The composite coating with a UTP:AR mass ratio of 1:1 (UTP/AR3) showed the best chemical resistance and light aging resistance. UTP/AR3 also exhibited a good corrosion current density (2.009 × 10⁻⁷ A cm⁻²) and corrosion potential (−0.5007 V), further indicating that the UTP/AR composite coatings have excellent anti-corrosive properties. Marine field tests showed that the UTP/AR/Cu₂O composite coatings with rosin-modified Cu₂O contents less than 20% showed stable, long-term antifouling performance after immersion in seawater for 360 day. Briefly, the UTP/AR/Cu₂O composite coatings have broad application prospects in the marine industry for materials in the spray splash zone.     

Synthesis,characterization, and evaluation of antifouling polymers of 4‐acryloyloxybenzaldehyde with methyl methacrylate

In recent years, antifouling (AF) polymers are widely used in marine paints to protect the ship hulls from biofouling. The AF polymer coatings have better leaching characteristics and long lasting efficiency than other conventional formulations. In this study, an attempt has been made to prepare new p‐acryloyloxybenzaldehyde(AcBA) polymers to assess their AF efficiency against marine microfoulers. The monomer, AcBA was prepared by the esterification reaction between p‐hydroxybenzaldehyde (HBA) and acryloyl chloride (Ac) in presence of triethylamine (TEA) in MEK at 0°C. The reaction was monitored by TLC and the prepared monomer was characterized by UV, IR, ¹H‐NMR and GC‐MS. The homo‐[poly(AcBA)] and co‐polymers [poly(AcBA‐co‐MMA)] were prepared by solution polymerization using BPO as initiator. To find out the AF activity of prepared polymers, representatives of marine microfoulers, shipfouling bacteria (Bacillus macroides and Pseudomonas aeruginosa) and microalgae (Amphora coffeaeformis and Navicula incerta) were screened. The contact toxicity and diatom attachment assays were conducted with prepared polymers and microfouling formation on coatings was also investigated using a tubular biofilm reactor. AF potential of these polymers coating is demonstrated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The Effects of Incorporated Silicone Oils and Calcium Carbonate on the Resistance to Settlement and the Antifouling Performance of a Silicone Elastomer

The surfaces of elastomeric coatings based on poly(dimethylsiloxane), unfilled or containing calcium carbonate filler or with filler and silicone oils, have been characterised from topographic and surface indentation measurements by atomic force microscopy. The resistance of the coatings to marine biofouling has been assessed in a sea-exposure trial, in which the strengths of attachment of some barnacles and tubeworms have been measured. In laboratory experiments, the materials have been challenged with oyster larvae (Crassotrea gigas), barnacle cyprids (Balanus amphitrite) and brown algal embryos (Sargassum muticum). Using a linear stress flow cell, the stresses required to detach settled larvae and embryos by fluid flow have been measured. The attachment of barnacles to the coatings was promoted by the microscopic surface roughness produced by protruding particles of filler. Oyster larvae and algal embryos were more readily displaced from surfaces that had been characterised as relatively soft, or from oil-bloomed surfaces.     

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.     

Effects of pigmentation on siloxane–polyurethane coatings and their performance as fouling-release marine coatings

Siloxane–polyurethane paints were formulated and characterized for coating properties and performance as fouling-release (FR) marine coatings. Paints were formulated at 20 and 30 pigment volume concentrations with titanium dioxide, and aminopropyl-terminated poly(dimethylsiloxane) (APT-PDMS) loadings were varied from 0 to 30% based on binder mass. The coatings were characterized for water contact angle, surface energy (SE), gloss, and pseudobarnacle (PB) adhesion. The assessment of the FR performance compared with polyurethane (PU) and silicone standards through the use of laboratory biological assays was also performed. Biofilm retention and adhesion were conducted with the marine bacterium Cellulophaga lytica, and the microalgae diatom Navicula incerta. Live adult barnacle reattachment using Amphibalanus amphitrite was also performed. The pigmented coatings were found to have properties and FR performance similar to those prepared without pigment. However, a higher loading of PDMS was required, in some cases, to obtain the same properties as coatings prepared without pigment. These coatings rely on a self-stratification mechanism to bring the PDMS to the coating surface. The slight reduction in water contact angle (WCA) and increase in pseudobarnacle release force with pigmentation suggests that pigmentation slowed or interfered with the self-stratification mechanism. However, increasing the PDMS loading is an apparent method for overcoming this issue, allowing for coatings having similar properties as those of clear coatings and FR performance similar to those of silicone standard coatings.     

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.     

Structure–property correlations of foul release coatings based on low hard segment content poly(dimethylsiloxane–urethane–urea)

We report the foul release characteristics of model poly(dimethylsiloxane–urethane–urea) (PDMSPU)-based coatings with a relatively lower hard segment content of 9 to 13.7 wt%. The PDMSPUs were prepared by facile moisture curing of isophorone diisocyanate-capped hydroxyalkyl-terminated PDMS. The surface free energies of the coatings were tuned (20–25 mJ/m²) by varying the hard segment content to be in the minimum adhesive regime (20–30 mJ/m²) of Baier’s curve pertaining to the relative amount of biofouling vs the critical surface tension of various chemical substrates. A series of complimentary analytical tools, namely ¹H NMR spectroscopy, small-angle x-ray scattering (SAXS), FTIR-attenuated total reflectance spectroscopy (FTIR-ATR), contact angle goniometry, marine field tests, and quantitative biofouling adhesion in shear, have been employed to deduce several physicochemical parameters of importance to establish the structure property correlations. Further, the time-dependant changes in surface wettability and surface concentration of polar functional groups of the coatings (immersed in 3.5 wt% aqueous solution of NaCl) were investigated by FTIR-ATR and contact angle goniometry. The extent of surface restructuring was found to increase with increasing hard segment content of the PDMSPUs and consequently increasing attachment strengths of macrofoulants with the coatings, which were in the range 0.12–0.5 MPa.     

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。     

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。     

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.     

Marine diatom Navicula jeffreyi from biochemical composition and physico-chemical surface properties to understanding the first step of benthic biofilm formation

To understand the first step of marine benthic microbial mat formation and biofouling phenomena, caused by diatoms in the marine environment, the surface properties of the epipelic diatom Navicula jeffreyi were studied and the composition of its bound Extracellular Polymeric Substances (EPS) was determined. These parameters are determining factors for the initial adhesion step of diatoms to other constituents that start marine fouling. Surface energy of a diatom cell layer was determined using the sessile drop technique and highlights that diatoms show a moderate hydrophobic character (contact angle with water >68°), no Lewis acid character (γ⁺?<1?mJ/m²), and a low Lewis basic character (γ^??=?16.1?mJ/m²). An extraction procedure using a cationic resin subtracted only the bound EPS. Biochemical assays showed that there were 2.5 times more proteins than sugars. The propensity of Navicula jeffreyi diatom to adhere to five different solid surfaces, showing a gradient in their hydrophobic and hydrophilic character, was measured. The attachment densities were high on hydrophobic surfaces such as polytetrafluoroethylene and very low on substrata with surface free energy over 40–50?mJ/m². Using a thermodynamic approach, the free energy of adhesion of the diatom to the five substrata was determined, and led to a very strong correlation with attachment densities for polytetrafluoroethylene, polyamide, polyethylene, and stainless steel.     

Transparent antifouling coatings via nanoencapsulation of a biocide

Transparent coatings releasing an antifouling agent (AF) can be used to reduce the marine fouling of optical lenses. A variety of water‐borne coatings based on poly(methyl methacrylate‐co‐butyl acrylate) (PMMA‐co‐PBA) were synthesized using a two‐stage miniemulsion process. During this process, the AF, SeaNine 211, was nanoencapsulated in domains small enough not to scatter light. The release rate of SeaNine 211 was studied for the polymers of different T_g, and found to be sufficient to impart AF properties. However, over time, the coatings were found to develop a whitish aspect (blushing) due to water retrodiffusion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

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.     

Dimethyl secondary amine chain extenders: a conceptual approach to in situ generation of advanced epoxy resins for rapid cure, low VOC coatings

Solid epoxy resin oligomers have traditionally been utilized for coatings that combine fast dry-to-touch speed and good flexibility, properties greatly in demand in many applications such as marine and industrial maintenance coatings. Unfortunately, solid epoxy resins require formulation with large quantities of solvent that make the attainment of modern VOC regulations difficult or impossible. Coatings formulated from low molecular weight liquid epoxy resin (LER) on the other hand, can more easily meet VOC challenges, but dry slowly and tend to be brittle. This article explores the concept of using fast reacting, difunctional amine chain extenders to generate epoxy oligomers in situ as a means of meeting these opposing property demands. Methylamine-terminated poly(N-methylazetidine) (p-NMAz) is prepared in a two-step process involving the Michael addition of methylamine to acrylonitrile followed by hydrogenation in a methylamine-containing atmosphere to yield an oligomer stream with an M _n of about 250. Hydrogenation of isophthalonitrile in a methylamine-containing atmosphere yields N,N′-dimethyl-meta-xylylenediamine (DMMXDA). Competitive pseudo-first-order kinetic measurements conducted in isopropyl alcohol indicate these amines react approximately 3–3.6 times faster with phenyl glycidyl ether (PGE) than the primary amine meta-xylylenediamine (MXDA). These chain extenders can be formulated with traditional multifunctional amine crosslinkers to yield coatings with lower VOC, faster dry speed, and better flexibility compared with corresponding coatings formulated without the chain extender. Consistent with their chemical structures, p-NMAz proved capable of yielding coatings with the best impact resistance and mandrel bend properties, while DMMXDA yielded coatings with better water and corrosion resistance properties.

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.     

Enhancement of graft density and chain length of hydrophilic polymer brush for effective marine antifouling

2‐Hydroxyethyl methacrylate polymer brushes with various grafting densities and chain lengths were prepared through surface‐initiated atom transfer radical polymerization. X‐ray photoelectron spectra, ellipsometry measurement, contact angle measurement, and atom force microscope were used to characterize the prepared polymer brush. The biofouling assays of polymer brush were investigated by adhesion of Dunaliella tertiolecta, Navcular sp., and Bovine Serum Albumin protein and by static marine immersion field test. Besides, hydroxyl and sulfonate‐terminated self‐assembled monolayers, anionic charged 3‐sulfopropyl methacrylate potassium salt polymer brush were prepared for comparison. Results suggest that the settlement of microorganisms can be largely reduced by polymer with enough polymer chain length and grafting density. More importantly, static immersion field tests indicate that hydrophilic polymer film with enough hydration layer thickness is necessary for long‐term marine antifouling application. This comprehensive investigation is of great importance to understanding their influence on the adhesion of marine microorganism. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46232.     

Effect of surface free energy on the adhesion of biofouling and crystalline fouling

Pipelines and heat exchangers using seawater as coolant suffer from biofouling. Biofouling not only reduces heat transfer performance significantly, but also causes considerable pressure drop, calling for higher pumping requirements. It would be much more desirable if surfaces with an inherently lower stickability for biofouling could be developed. In this paper, a cost-effective autocatalytic graded Ni-Cu-P-PTFE composite coating with corrosion-resistant properties was applied to reduce biofouling formation. The experimental results showed that the surface free energy of the Ni-Cu-P-PTFE coatings, which were altered by changing the PTFE content in the coatings, had a significant influence on the adhesion of microbial and mineral deposits. The Ni-Cu-P-PTFE coatings with defined surface free energy reduced the adhesion of these deposits significantly. The anti-bacterial mechanism of the composite coatings was explained with the extended DLVO theory.     

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     

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.