Formation of antifouling functional coating from deposition of a zwitterionic-co-nonionic polymer via “grafting to” approach

We develop a new process for the preparation of synergistic antifouling functional coatings on gold surfaces via a “grafting to” approach. The strategy includes a synthetic step of polymer brushes that consist of poly (ethylene glycol) (PEG) and zwitterionic side chains via a typical reversible-addition fragmentation chain transfer (RAFT) polymerization process, and a subsequent deposition of the polymer brushes onto a gold substrate. The presence of PEG and zwitterion chains on these polymer brush-coated gold surfaces has been proved to have a synergistic effect on the final antifouling property of the coating. PEG chains lower the electrostatic repulsion between zwitterionic polymer chains and increase their graft density on gold surfaces, while zwitterionic polymer effectively improves the antifouling property that is offered by PEG chains alone. Protein adsorption and cell attachment assays tests are conducted to confirm that this copolymer layer on gold surface has a pronounced resistance against proteins such as Bovine serum albumin and Lysozyme. Importantly, the antifouling property can be systematically adjusted by varying the molar ratio of PEG to zwitterionic chains in the final coating copolymer.     

水性防污涂料的研究进展

海洋污损生物是海洋资源开发首先要面对的问题。防污涂料是防除海洋污损生物的关键材料。传统的防污涂料虽然发展成熟,但以油性溶剂为介质,存在挥发性有机物(VOC)排放过高、环境污染严重的问题。不释放VOC的水性涂料符合绿色无污染的环保要求,是防污材料领域研究的热点。本文对最重要的四种水性防污涂料(污损释放型水性低表面能防污涂料、自抛光型水性防污涂料、污损阻抗型水凝胶海洋防污涂料、强碱释放型水性硅酸盐防污涂料)从防污机理、制备方法和存在的问题等几个方面进行了综述,并对水性防污涂料的发展趋势进行了展望。     

Synthesis and Bacteriostatic Activity and Antifouling Capability of Benzamide Derivatives Containing Capsaicin

Five benzamide deriatives containing capsaicin were synthesized which have similar structures to capsaicin. Their yield was high. The monomers synthesized were characterized by IR, 1H NMR and MS spectroscopy. Characterization data are in agreement with the proposed structures of the products. These five compounds exhibit bacterial inhibition and N-[4-hydroxy-2-methyl-5-(methylthio)benzyl]benzamide(HMMBBA), for instance, shows that the minimal inhibitory concentrations(MIC) of HMMBBA are 0.125 and 0.25 mg/mL on Staphyloccocus aureus and Escherichia coli, respectively. A static test site was set up in the eighth harbor to investigate the antifouling effectiveness of the five new antifoulants. Five-month exposure experiments were performed on sets of panels coated with each of antifouling coatings, and the results were compared to that of the test panel without antifouling coating. Test boards with antifouling coating were covered with just a macroscopic fouling organism such as Balanus. The results of the present paper demonstrate that new antifoulants represent an alternative to the biocidal antifouling paint.     

溶菌酶蛋白在聚合物防污膜表面的吸附

采用分子动力学模拟方法比较了溶菌酶蛋白在两种典型聚合物防污材料聚乙二醇(PEG)和聚二甲基硅氧烷(PDMS)表面的吸附行为, 在微观上探讨了聚合物膜表面性质对蛋白质吸附的影响. 根据蛋白质与聚合物膜之间的相互作用、能量变化及表面水化层分子的动力学行为, 解释了PEG防污涂层相对于PDMS表面具有更佳防污效果的原因: (1) 相比PDMS涂层, 蛋白质与PEG涂层的结合能量较低, 使其结合更加疏松; (2) 蛋白质吸附到材料表面要克服表面水化层分子引起的能障, PEG表面与水分子之间结合紧密, 结合水难于脱附, 造成蛋白质在其表面的吸附需要克服更高的能量, 不利于蛋白质的吸附.     

溶菌酶蛋白在聚合物防污膜表面的吸附

采用分子动力学模拟方法比较了溶菌酶蛋白在两种典型聚合物防污材料聚乙二醇(PEG)和聚二甲基硅氧烷(PDMS)表面的吸附行为,在微观上探讨了聚合物膜表面性质对蛋白质吸附的影响.根据蛋白质与聚合物膜之间的相互作用、能量变化及表面水化层分子的动力学行为,解释了PEG防污涂层相对于PDMS表面具有更佳防污效果的原因:(1)相比PDMS涂层,蛋白质与PEG涂层的结合能量较低,使其结合更加疏松;(2)蛋白质吸附到材料表面要克服表面水化层分子引起的能障,PEG表面与水分子之间结合紧密,结合水难于脱附,造成蛋白质在其表面的吸附需要克服更高的能量,不利于蛋白质的吸附.     

Silicone-enriched surface of immersed polyurethane-POSS antifouling coating

Abstract

A series of waterborne polyurethane-polyhedral oligomeric silsesquioxane (WBPU-POSS) dispersions were synthesized. Different POSS contents were used to evaluate the effect of POSS content on silicone enrichment under both nonimmersed and immersed conditions. The impact of silicone enrichment under immersed conditions on antifouling properties was also evaluated. The structure of the WBPU-POSS coating was identified by FT-IR and ²⁹Si-NMR. X-ray photoelectron spectroscopy (XPS) analysis confirmed a silicone-enriched surface with a certain composition of the WBPU-POSS coating under both nonimmersed and immersed conditions. The mechanical properties, hydrophilicity and hydrolytic degradation of the coating all varied with POSS content. The long-term antifouling performance of immersed coatings depends on surface silicone enrichment, which was found to be above 0.0021?mole POSS content in WBPU-POSS coatings.     

Development of multifunctional polydimethylsiloxane (PDMS)‐epoxy‐zinc oxide nanocomposite coatings for marine applications

Multifunctional epoxy‐polydimethylsiloxane nanocomposite coatings with antifouling and anticorrosion characteristics have been developed via in situ polymerization method at different loading (1, 3, and 6.5 wt.%) of ZnO nanoparticles to cater marine applications. A detailed comparative analysis has been carried out between epoxy‐polydimethylsiloxane control (EPC) and ZnO‐reinforced coatings to determine the influence of ZnO loading on various properties. The incorporation of ZnO in EPC led to increase in root mean square (RMS) roughness to 126.75 nm and improved hydrophobicity showing maximum contact angle of 123.5° with low surface energy of 19.75 mN/m of nanocomposite coating as compared with control coating. The differential scanning calorimetry (DSC) result indicated improved glass transition temperature of nanocomposite coatings with highest T_g obtained at 83.69°C in case of 1 wt.% loading of ZnO. The increase in hydrophobicity of the system was accompanied by upgraded anticorrosion performance exhibiting 98.8% corrosion inhibition efficiency (CIE) as compared with control coating and lower corrosion rate of 0.12 × 10^?3 mm/year. The Taber abrasion resistance and pull‐off adhesion strength results indicated an increment of 34.7% and 150.7%, respectively, in case of nanocomposite coating as compared with the control coating. The hardness of nanocomposite coatings was also improved, and maximum hardness was found to be 65.75 MPa for nanocomposite coating with 1 wt.% of ZnO. Our study showed that the nanocomposite coating was efficient in inhibiting accumulation of marine bacteria and preventing biofouling for more than 8 months. The developed environment‐friendly and efficient nanocomposite material has a promising future as a high‐performance anticorrosive and antifouling coating for marine applications.     

无机填料在改性两亲性水凝胶防污材料中的应用研究

水凝胶防污材料因其环保特性成为当前海洋防污领域的研究热点,然而其黏附及力学性能的不足仍是限制其实际应用的技术关键。本研究在油性结构单元增加黏附的两亲性水凝胶的基础上,通过物理共混引入Al₂O₃、 TiO₂、蒙脱土和高岭土赋予两亲性水凝胶涂层更多的黏附机制并考察它们对水凝胶涂层其它性能的影响。研究发现,随着无机填料的引入和含量的增加,水凝胶涂层的黏附性能大幅增加,静态泡板和动态划水的不脱落时间分别提高6倍和2.5倍。其中,TiO₂和高岭土能使水凝胶涂层的应力明显增强。虽然,无机填料的加入使两亲性水凝胶涂层抑制牛血清蛋白及小新月菱形藻吸附的能力下降,但在实海挂板实验中依然表现出相当的防污能力,且具有一定的实际应用价值。本研究为探讨无机填料对水凝胶涂层性能的影响提供了一些参考,并对提高两亲性水凝胶涂层黏附及力学性能提供了一种策略。     

An Ethylenediamine‐based Switch to Render the Polyzwitterion Cationic at Tumorous pH for Effective Tumor Accumulation of Coated Nanomaterials

Polyzwitterions are employed as coating polymers for biomaterials to induce an antifouling property on the surface. Fine‐tuning the betaine structure switches the antifouling property to be interactive with anionic tissue constituents in response to a tumorous pH gradient. The ethylenediamine moiety in the carboxybetaine enabled stepwise protonation and initiated the di‐protonation process around tumorous pH (6.5). The net charge of the developed polyzwitterion (PGlu(DET‐Car)) was thus neutral at pH 7.4 for antifouling, but was cationic at pH 6.5 for interaction with anionic constituents. Quantum dots coated with PGlu(DET‐Car) exhibited comparable stealth and enhanced tumor accumulation relative to the PEG system. The present study provides a novel design of smart switchable polyzwitterion based on a precise control of the net charge.     

含氟/PEG的有机硅基双亲防污涂层的制备及性能

以不同分子量的端氢硅油(PDMS)和聚乙二醇二烯丙基醚(PEGDE)为原料,通过硅氢加成合成了系列双键封端的含有机硅和聚乙二醇(PEG)链段的多嵌段共聚物(PDMS-b-PEG)m,再用三甲氧基氢硅烷进行端基官能化,生成三甲氧基硅烷封端的多嵌段聚合物,即含PEG前驱物.含PEG前驱物、含氟前驱物(FMS-9922)与有机硅基体树脂通过缩合聚合制备了含PEG的氟硅双亲弹性防污涂层.通过核磁共振氢谱、红外光谱对PEG前驱物的结构进行了表征.吸水率、SEM-EDS和接触角测试考察了含PEG前驱物中疏水链段的长度,含氟前驱物的含量对涂层表面重排的影响,结果表明PEG前驱物中疏水链段越长,涂层的吸水率越低,在水中越稳定,且表面不易发生重排.而含氟前驱物的加入能促使PEG链段向表面方向迁移.抗蛋白、抗菌和抗藻附着性能测试表明:含有FMS-9922的样品防污性能均优于不含FMS-9922的样品,而且随着FMS-9922用量增加,涂层防污性能呈上升趋势;但是FMS-9922用量太高时,体系相容性下降,防污性能也随之变差,故FMS-9922的含量控制在7%为宜.     

Synthesis and Quantum Chemical Calculation of Benzamide Derivatives Containing Capsaicin and Their Bacteriostatic and Antifouling Properties

Thirteen benzamide derivatives containing capsaicin (BDCCs) have been successfully synthesized via the current method (Friedel‐Crafts alkylation reaction). The resultant monomers were characterized by IR, ¹H and ¹³C NMR, elemental analysis and HRMS. Characterization results were in agreement with the proposed structures of the products. Quantum chemistry calculation yielded three parameters, namely, Δε_L‐H, HF values (total energy) and dipole that could explain activity, stability and polarity respectively, and the relationship of each parameter with antimicrobial and antifouling performance was also preliminary discussed. The bacteriostatic property of the 13 compounds was evaluated by minimum inhibitory concentration (MIC) and bacteriostatic ring tests. Experimental results indicated that these compounds can inhibit Staphylococcus aureus and Escherichia coli. The antifouling effectiveness of the novel antifoulants was investigated using panel tests at the eighth harbor, Qingdao. Four‐month exposure results were compared. The compounds exhibited better antifouling properties than the blank panel without antifouling coating or the panel with a common coating. However, test panels with the antifouling coatings were covered with trace amounts of algae and Balanus because of weakening of antifouling ability over extended periods of time. All results demonstrate that the new compounds synthesized via our method can be applied in environment‐friendly antifouling paints.     

The antifouling and fouling-release performance of hyperbranched fluoropolymer (HBFP)-poly(ethylene glycol) (PEG) composite coatings evaluated by adsorption of biomacromolecules and the green fouling alga Ulva

Cross-linked hyperbranched fluoropolymer (HBFP) and poly(ethylene glycol) (PEG) amphiphilic networks with PEG weight percentages of 14% (HBFP-PEG14), 29% (HBFP-PEG29), 45% (HBFP-PEG45), and 55% (HBFP-PEG55) were prepared on 3-aminopropyl)triethoxysilane (3-APS) functionalized microscope glass slides for marine antifouling and fouling-release applications. The surface-free energies (gamma(s)), polar (gamma(s)(p) and gamma(s)(AB)), and dispersion (gamma(s)(d) and gamma(s)(LW)) components were evaluated using advancing contact angles by two-liquid geometric-mean and three-liquid Lifshitz-van der Waals acid-base approaches. The HBFP coating exhibited a low surface energy of 22 mJ/m(2), while the gamma(s) and gamma(s)(p) of the cross-linked HBFP-PEG coatings increased proportionally with the PEG weight percentages in the networks. The adsorption of bovine serum albumin (BSA), lectin from Codium fragile (CFL), lipopolysaccharides from Escherichia coli (LPSE) and Salmonella minnesota (LPSS) upon glass, APS-glass, HBFP, PEG, and the cross-linked HBFP-PEG network coatings were investigated by fluorescence microscopy. The marine antifouling and fouling-release properties of the cross-linked HBFP-PEG coatings were evaluated by settlement and release assays involving zoospores of green fouling alga Ulva (syn. Enteromorpha; Hayden, H. S.; Blomster, J.; Maggs, C. A.; Silva, P. C.; Stanhope, M. J.; Waaland, J. R. Eur. J. Phycol. 2003, 38, 277). The growth and release of Ulva sporelings were also investigated upon the HBFP-PEG45 coating in comparison to a poly(dimethylsiloxane) elastomer (PDMSE) standard material. Of the heterogeneous cross-linked network coatings, the maximum resistances to protein, lipopolysaccharide, and Ulva zoospore adhesion, as well as the best zoospore and sporeling release properties, were recorded for the HBFP-PEG45 coating. This material also exhibited better performance than did a standard PDMSE coating, suggesting its unique applicability in fouling-resistance applications.     

EB/UV treatment of protective coatings for porous materials

A method for improving surface properties of porous inorganic materials is presented. The method is particularly tailored to cement-based materials in order to obtain properties suitable for mechanical applications such as dies manufacturing, where hardness, abrasion resistance and low friction are requested. The coating system is based upon using two coatings of different characteristics. The underlying base coating layer is infiltrated in air on three different formulations of hardened cement composite. Two different bi-component resins, one relatively soft and the other relatively hard, were tested as underlying surface coating. The outer surface coating, based upon a bi-component resin characterized by high hardness, is added after hardening and curing of the first layer. Both coatings were chemically hardened and then cured with EB. UV curing is also suitable for the outer surface coating. An experimental campaign was carried out in order to evaluate the influence of radiation processing as curing treatment with reference to particular investigated materials. Hardness and resistance to peeling of coating systems have been measured and are presented.     

Zwitterionic Polysulfobetaine Coating and Antiplatelet Liposomes Reduce Fouling in Artificial Lung Circuits

The artificial lung has provided life-saving support for pulmonary disease patients and recently afforded patients with severe cases of COVID-19 better prognostic outcomes. While it addresses a critical medical need, reducing the risk of clotting inside the device remains challenging. Herein, a two-step surface coating process of the lung circuit using Zwitterionic polysulfobetaine methacrylate is evaluated for its nonspecific protein antifouling activity. It is hypothesized that similarly applied coatings on materials integrated (IT) or nonintegrated (NIT) into the circuit will yield similar antifouling activity. The effects of human plasma preconditioned with nitric oxide-loaded liposome on platelet (plt) fouling are also evaluated. Fibrinogen antifouling activities in coated fibers are similar in the IT and NIT groups. It however decreases in coated polycarbonate (PC) in the IT group. Also, plt antifouling activity in coated fibers is similar in the IT and NIT groups and is lower in coated PC and Tygon in the IT group compared to the NIT group. Coating process optimization in the IT lung circuit may help address difference in the coating appearance of outer and inner fiber bundle fibers, and the NO-liposome significantly reduces (86%) plt fouling on fibers indicating its potential use for blood anticoagulation.     

PANI-PMMA as cathodic electrode material and its application in cathodic polarization antifouling

Cathodic voltage applied to metal substrata has been proven to exhibit useful antifouling properties due to the generation of H₂O₂, where the metal substratum is used as a cathode in the process. However, most metals immersed in a marine environment are protected by insulating (anticorrosive) coatings, restricting the cathodic polarization that can be applied to the metal. In this work, polyaniline-polymethyl methacrylate was found to have good stability and low background current density, as measured by linear sweep voltammetry (LSV), chronoamperometry (CA) and cyclic voltammetry (CV), suggesting potential for use of PANI-PMMA as a cathode material. The antifouling effects of the PANI-PMMA coating on 24-h-old Escherichia coli bacteria (E. coli) were measured under different cathodic potentials and different polarization times; the outstanding antifouling effect was verified by fluorescence microscopy.     

An Overview of Antifouling Strategies for Electrochemical Analysis

Fouling is a key issue which limits the practical applications of electrochemical sensors (ECSens) in both in vitro and in vivo analysis. The analytical sensitivity, limit of detection (LOD), selectivity, reproducibility and life-time of ECSens are all greatly affected by fouling. Although numerous methods and materials have been developed to minimize the fouling effect in past several decades, not all of them are suitable for constructing antifouling ECSens. In this paper we present an overview of surface antifouling strategies for ECSens. We begin with a short summary of sources and impacts of fouling under both in vitro and in vivo environments. Then the current surface antifouling strategies for ECSens are discussed, including self-assembled monolayers (SAMs), antifouling polymers, porous coating, in-situ electrochemical and photocatalytic cleaning. The antifouling mechanisms, advantages and challenges of each strategy are briefly summarized. The article ends up with a short conclusion and perspectives. We hope this article is helpful for constructing and designing ECSens with both outstanding antifouling performance and electrochemical activity for electrochemical analysis.     

海洋污损生物粘附机制及防污涂层表面工程

任何浸入海水的结构物均会受到海洋污损生物的附着。 在物体表面涂覆防污涂料是最广泛的防污方式,无毒污损脱附型防污涂料已成为当前的研究热点。 分析了污损生物的粘附过程及界面粘结作用,探讨了表面能、涂层模量、表面化学成分、微观形貌、颜色等因素对涂层防污效果的影响,并指出涂料工程化中必须解决的问题。     

原位探测防污高分子材料与液体界面的分子结构

Marine organisms such as plants, algae or small animals can adhere to surfaces of materials that are submerged in ocean. The accumulation of these organisms on surfaces is a marine biofouling process that has considerable adverse effects. Marine biofouling on ship hulls can cause severe fuel consumption increase. Investigations on antifouling polymers are therefore becoming important research topics for marine vessel operations. Antifouling polymers can be applied as coating layers on the ship hull, protecting it against the settlement and growth of sea organisms. Polyethylene glycol (PEG) is a hydrophilic polymer that can effectively resist the accumulation of marine organisms. PEG-based antifouling coatings have therefore been extensively researched and developed. However, the inferior stability of PEG makes it subject to degradation, rendering it ineffective for long-term services. Zwitterionic polymers have also emerged as promising antifouling materials in recent years. These polymers consist of both positively charged and negatively charged functional groups. Various zwitterionic polymers have been demonstrated to exhibit exceptional antifouling properties. Previously, surface characterizations of zwitterionic polymers have revealed that strong surface hydration is critical for their antifouling properties. In addition to these hydrophilic polymers, amphiphilic materials have also been developed as potential antifouling coatings. Both hydrophobic and hydrophilic functional groups are incorporated into the backbones or sidechains of these polymers. It has been demonstrated that the antifouling performance can be enhanced by precisely controlling the sequence of the hydrophobic-hydrophilic functionalities. Since biofouling generally occurs at the outer surface of the coatings, the antifouling properties of these coatings are closely related to their surface characteristics in water. Therefore, understanding of the surface molecular structures of antifouling materials is imperative for their future developments. In this review, we will summarize our recent advancements of antifouling material surface analysis using sum frequency generation (SFG) vibrational spectroscopy. SFG is a surface-sensitive technique which can provide molecular information of water and polymer structures at interfaces in situ in real time. The antifouling polymers we will review include zwitterionic polymer brushes, mixed charged polymers, and amphiphilic polypeptoids. Interfacial hydration studies of these polymers by SFG will be presented. The salt effect on antifouling polymer surface hydration will also be discussed. In addition, the interactions between antifouling materials and protein molecules as well as algae will be reviewed. The above research clearly established strong correlations between strong surface hydration and good antifouling properties. It also demonstrated that SFG is a powerful technique to provide molecular level understanding of polymer antifouling mechanisms.     

包埋苯甲酸钠微球的制备及在海洋防污涂料中的抑菌研究

用溶剂挥发法制备了可以包埋海洋防污剂苯甲酸钠的聚苯乙烯聚合物微球,并实现了防污剂在海洋防污涂料中的的缓慢释放.讨论了影响微球性能的一些因素,聚合物微球的粒径分别随着温度的降低,分散剂浓度的升高以及搅拌速度的提高而减小.采用标准曲线法,对防污剂释放速度进行了分析,并与未用微球包埋的苯甲酸钠释放速度进行对比,缓释效果明显....     

New peptidomimetic polymers for antifouling surfaces

Exposure of therapeutic and diagnostic medical devices to biological fluids is often accompanied by interfacial adsorption of proteins, cells, and microorganisms. Biofouling of surfaces can lead to compromised device performance or increased cost and in some cases may be life-threatening to the patient. Although numerous antifouling polymer coatings have enjoyed short-term success in preventing protein and cell adsorption on surfaces, none have proven ideal for conferring long-term biofouling resistance. Here we describe a new biomimetic antifouling N-substituted glycine polymer (peptoid) containing a C-terminal peptide anchor derived from residues found in mussel adhesive proteins for robust attachment of the polymer onto surfaces. The methoxyethyl side chain of the peptoid portion of the polymer was chosen for its chemical resemblance to the repeat unit of the known antifouling polymer poly(ethylene glycol) (PEG), whereas the composition of the 5-mer anchoring peptide was chosen to directly mimic the DOPA- and Lys-rich sequence of a known mussel adhesive protein. Surfaces modified with this biomimetic peptide-peptoid conjugate exhibited dramatic reduction of serum protein adsorption and resistance to mammalian cell attachment for over 5 months in an in vitro assay. These new synthetic peptide based antifouling polymers may provide long-term control of surface biofouling in the physiologic, marine, and industrial environments.