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1.
Langmuir ; 40(28): 14281-14290, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38967331

RESUMO

Marine antibiofouling using low-amplitude electric pulses (EP) is an energy-efficient and eco-friendly approach, but potential mechanisms for preventing biofouling remain unclear. In the present study, the 3D adhesion dynamics of a model microorganism─Pseudomonas aeruginosa (PAO1)─under low-amplitude cathodic EP were examined as a function of applying voltage and its duration (td). The results demonstrated that adhered bacteria escaped from the electrode surface even when EP was removed. The escaped bacteria ratio, induction period of escape, and duration of the detachment were influenced profoundly by EP amplitude but slightly by td when td ≥ 5 min. The acceleration of escaped PAO1 from the surface indicated that their flagellar motor was powered by EP. Particularly, EP enabled swimming bacteria to have adaptive motions that were sustainable and regulated by the gene rsmA. As a result, they had less accumulation near the surface. The propulsion of adhered bacteria and adaptive escape of swimming bacteria were enhanced in response to low-amplitude EP. Hence, low-amplitude and short-duration EP is promising for sustainable antibiofouling applications.


Assuntos
Aderência Bacteriana , Pseudomonas aeruginosa , Pseudomonas aeruginosa/fisiologia , Eletrodos , Eletricidade , Incrustação Biológica/prevenção & controle
2.
Angew Chem Int Ed Engl ; : e202410335, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967098

RESUMO

Ionogels are promising for soft iontronics, with their network structure playing a pivotal role in determining their performance and potential applications. However, simultaneously achieving mechanical toughness, low hysteresis, self-healing, and fluorescence using existing network structures is challenging. Drawing inspiration from jellyfish, we propose a novel hierarchical crosslinking network structure design for in situ formation of hyperbranched cluster aggregates (HCA) to fabricate polyurea ionogels to overcome these challenges. Leveraging the disparate reactivity of isocyanate groups, we induce the in situ formation of HCA through competing reactions, enhancing toughness and imparting the clustering-triggered emission of ionogel. This synergy between supramolecular interactions in the network and plasticizing effect in ionic liquid leads to reduced hysteresis of the ionogel. Furthermore, the incorporation of NCO-terminated prepolymer with dynamic oxime-urethane bonds (NPU) enables self-healing and enhances stretchability. Our investigations highlight the significant influence of HCA on ionogel performance, showcasing mechanical robustness including high strength (3.5 MPa), exceptional toughness (5.5 MJ m-3), resistance to puncture, and low hysteresis, self-healing, as well as fluorescence, surpassing conventional dynamic crosslinking approaches. This network design strategy is versatile and can meet the various demands of flexible electronics applications.

3.
ACS Appl Mater Interfaces ; 16(20): 26733-26742, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38718383

RESUMO

Polyurea has found applications in protective coatings. Yet, the too fast polymerization and lack of functions limit its application. Herein, we report a high-performance polyurea via the stepwise polymerization of an isocyanate (NCO)-terminated prepolymer consisting of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPG-b-PEG-b-PPG) with a nanocluster synthesized via the hydrolysis of N-phenylaminomethyltriethoxysilane. Such a nanocluster contains low-reactivity secondary amines, so the polymerization of polyurea can be slowed down (over 1 h), which improves its wetting and adhesion to a substrate. The residual silanol groups on the nanocluster further increase the adhesion. Such polyurea exhibits high adhesion on various substrates, including glass, ceramic, steel, copper, titanium, wood, and natural rubber (∼2.35-14.64 MPa). Besides, the nanoclusters can cross-link the prepolymer into a tough network, endowing the polyurea with a high mechanical strength of ∼25 MPa, much higher than the traditional polyaspartic ester polyurea. On the other hand, the PEG segments enable the polyurea to have good fouling resistance against proteins (fibrinogen absorption was reduced by over 90%), bacteria (RBA of S. aureusE. coli and Pseudomonas sp. was less than 10%), as well as diatom (diatom density was less than 100 cells/mm2). The polyurea is expected to find applications in biomedical engineering and marine antifouling.

4.
Mater Horiz ; 11(13): 3143-3156, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38629134

RESUMO

High-performance elastomers are essential in daily life and various industrial sectors such as personal protection, soft electronics, and vibration control. Nevertheless, despite massive efforts, concurrently achieving ultrahigh flexibility and remarkable impact resistance continues to be elusive. Herein, we report an innovative modular construction strategy that employs a topology-tailoring polymer network consisting of stereoscopic (epoxy-oligosiloxane nanoclusters) and linear (amino-terminated polyurea) building blocks as independent modules to develop intelligent anti-impact elastomers via an epoxy-amine mechanism. By precisely tailoring the topology of building blocks, the elastomers demonstrate high flexibility and toughness, remarkable impact responsiveness and ultrahigh energy dissipation. Their anti-impact ability surpasses those of most common soft and rigid materials such as steel, plastic, rubber, foam, or even polyborosiloxane. Moreover, the elastomers are well-qualified for use in flexible display technologies, owing to their high transparency (>92% transmittance), exceptional fold-resistance (no creasing after 10 000 bends), and good thermal stability (no discoloration at 100 °C). Furthermore, the elastomers exhibit excellent versatility, enabling them to be combined with either soft or rigid materials to generate composites with ultrahigh puncture and ballistic resistance. This study offers a promising framework for the design and fabrication of intelligent anti-impact elastomers and provides valuable insights into the development of next-generation protective materials.

5.
Adv Mater ; 36(29): e2313495, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38683961

RESUMO

Underwater adhesives hold significant relevance in daily life and numerous industrial applications. Despite considerable efforts, developing scalable, high-performance underwater adhesives through a simple and effective method remains a formidable challenge. This study presents a novel mesh-tailoring strategy for in situ, rapid, and ultrastrong oleogel-based underwater adhesives (OUA), which comprises a highly crosslinked polyurethane network with a matching mesh size (≈2.22 nm) that precisely entraps bio-based epoxidized soybean oil (ESO) molecules (≈2.31 nm) by steric hindrance effect. This oleogel exhibits unprecedented robust mechanical properties (≈35 MPa) and maintains stability under extreme conditions, including high temperatures (100 °C), high pressures (30 MPa), and immersion in various solvents (water, ethanol, or ESO). In particular, this oleogel displays high hydrophobicity, rapid curing, and strong interface affinity, resulting in ultrahigh underwater adhesion strength (up to 2.13 MPa) and exceptional substrate universality. Moreover, the remarkable environmental adaptability and stability of OUA enable its use in harsh aqueous environments, including acidic/alkaline, saline, and extreme temperature solutions. The comprehensive capabilities of the OUA underscore its potential for building underwater structures, repairing leaky containers, and sealing broken submarine pipelines. This research establishes the foundation for the designing of next-generation underwater adhesives and offers fresh perspectives for exploring oleogel-based materials.

6.
Soft Matter ; 20(1): 192-200, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38073481

RESUMO

Biofilms are initially formed by substances such as proteins secreted by bacteria adhering to a surface. To achieve a durable antibacterial material, biodegradable dihydroxyl-terminated poly[(ethylene oxide)-co-(ethylene carbonate)] (PEOC(OH)2) with anti-protein adsorption properties was synthesized in this study. Further polycondensation of PEOC(OH)2 and isophorone diisocyanate (IPDI) led to biodegradable polyurethane (PEOC-PU) with PEOC as the soft segment. For comparison, polyurethanes with polyethylene glycol (PEG-PU) and polypropylene glycol (PPG-PU) as soft segments were also synthesized. The chemical structures of the polyurethanes were characterized by 1H NMR and FTIR. The biodegradation behavior of PEOC-PU promoted by lipase due to the presence of ethylene carbonate units was also studied. Their resistance to proteins was studied using quartz crystal microbalance with dissipation (QCM-D) and the results revealed that PEOC-PU exhibited excellent nonspecific resistance to proteins. The colonization of microorganisms on PU in the liquid culture medium was further examined and the results showed that PEOC-PU exhibited excellent antibacterial adhesion performance due to its protein resistance and biodegradation.


Assuntos
Poliuretanos , Proteínas , Poliuretanos/química , Adsorção , Polietilenoglicóis/química , Antibacterianos , Materiais Biocompatíveis/química
7.
Heliyon ; 9(3): e14231, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36911880

RESUMO

The ability to accurately forecast the spread of coronavirus disease 2019 (COVID-19) is of great importance to the resumption of societal normality. Existing methods of epidemic forecasting often ignore the comprehensive analysis of multiple epidemic prevention measures. This paper aims to analyze various epidemic prevention measures through a compound framework. Here, a susceptible-vaccinated-infected-recovered-deceased (SVIRD) model is constructed to consider the effects of population mobility among origin and destination, vaccination, and positive retest populations. And we further use real-time observations to correct the model trajectory with the help of data assimilation. Seven prevention measures are used to analyze the short-term trend of active cases. The results of the synthetic scene recommended that four measures-improving the vaccination protection rate (IVPR), reducing the number of contacts per person per day (RNCP), selecting the region with less infected people as origin A (SES-O) and limiting population flow entering from A to B per day (LAIP-OD)-are the most effective in the short-term, with maximum reductions of 75%, 53%, 35% and 31%, respectively, in active cases after 150 days. The results of the real-world experiment with Hong Kong as the origin and Shenzhen as the destination indicate that when the daily vaccination rate increased from 5% to 9.5%, the number of active cases decreased by only 7.35%. The results demonstrate that reducing the number of contacts per person per day after productive life resumes is more effective than increasing vaccination rates.

8.
ACS Appl Mater Interfaces ; 15(4): 5998-6004, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36683575

RESUMO

Flexible hard coatings with strong adhesion are critical requirements for several foldable devices and marine applications; however, only a few such coatings have been reported. Herein, we report a non-isocyanate polyurethane (NIPU) coating prepared by the epoxy-oligosiloxane nanocluster-amine curing reaction and cyclic carbonate-amine polyaddition, where the former provides the coating with ceramic-like hardness and polymer-like flexibility while the latter polymerization results in NIPU with strong substrate adhesion. The coating is transparent (>92% transmittance), hard (5-7 H), and flexible (2 mm bending diameter). It has strong adhesion to various substrates including aluminum alloy, titanium, steel, glass, ceramic, epoxy, and polyethylene terephthalate (2-8 MPa), which can be attributed to the high density of polar groups in NIPU. Moreover, we can facilely endow the coating with anti-icing, self-cleaning, and anti-smudge capabilities by incorporating amine-terminated low-surface-tension polydimethylsiloxane (PDMS) to replace a part of the amine curing agent. Particularly, the mechanical properties of NIPU coatings are only slightly affected by the introduction of low-content PDMS since it intends to enrich on the surface. The novel coating has promising future for use in fields of foldable devices and marine applications.

9.
Front Microbiol ; 13: 906345, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35875539

RESUMO

Marine biofouling caused huge economic losses of maritime industries. We aim to develop high-efficient, less-toxic, and cost-effective antifoulants to solve the problems of biofouling. In this study, we described the antifouling compounds albofungin and its derivatives (albofungin A, chrestoxanthone A, and chloroalbofungin) isolated from the metabolites of bacterium Streptomyces chrestomyceticus BCC 24770, the construction of high-yield strains for albofungin production, and application of albofungin-based antifouling coatings. Results showed that these albofungins have potent antibiofilm activities against Gram-positive and Gram-negative bacteria and anti-macrofouling activities against larval settlement of major fouling organisms with low cytotoxicity. With the best antifouling activity and highest yield in bacterial culture, albofungin was subsequently incorporated with hydrolyzable and degradable copolymer to form antifouling coatings, which altered biofilm structures and prevented the settlement of macrofouling organisms in marine environments. Our results suggested that albofungins were promising antifouling compounds with potential application in marine environments.

10.
Acc Chem Res ; 55(11): 1586-1598, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35544330

RESUMO

Marine organisms such as barnacle larvae and spores of algae adhere to underwater surfaces leading to marine biofouling. This phenomenon has numerous adverse impacts on marine industries and maritime activities. Due to the diversity of fouling organisms and the complexity of the marine environment, it is a huge challenge to combat marine biofouling, which limits the development and utilization of marine resources. Since the International Marine Organization banned the use of tributyltin self-polishing copolymer (SPC) coatings in 2008, the development of an environmentally friendly and efficient anti-biofouling polymer has been the most important task in this field. Tin-free SPC is a well-established and widely used polymer binder for anti-biofouling coating today. Being a nondegradable vinyl polymer, SPC exhibits poor anti-biofouling performance in static conditions. Even more, such nondegradable polymers were considered to be a source of microplastics by the International Union for the Conservation of Nature in 2019. Recently, numerous degradable polymers, which can form dynamic surface through main chain scission, have been developed for preventing marine biofouling in static conditions. Nevertheless, the regulation of their degradation and mechanical properties is limited, and they are also difficult to functionalize. A new polymer combining the advantages of vinyl polymers and degradable polymers is needed. However, such a combination is a challenge since the former are synthesized via free radical polymerization whereas the latter are synthesized via ring-opening polymerization.In this Account, we review our recent progress toward degradable vinyl polymers for marine anti-biofouling in terms of polymerization methods and structures and properties of polymers. First, we introduce the strategies for preparing degradable vinyl polymers with an emphasis on hybrid copolymerization. Then, we present the synthesis and performance of degradable and hydrolyzable polyacrylates, degradable polyurethanes with hydrolyzable side groups, and surface-fragmenting hyperbranched polymers. Polymers with degradable main chains and hydrolyzable side groups combine the advantages of SPC and degradable polymers, so they are degradable and functional. They are becoming new-generation polymers with great potential for preparing high-efficiency, long-lasting, environmentally friendly and broad-spectrum coatings to inhibit marine biofouling. They can also find applications in wastewater treatment, biomedical materials, and other fields.


Assuntos
Incrustação Biológica , Incrustação Biológica/prevenção & controle , Plásticos , Polimerização , Polímeros/química , Propriedades de Superfície
11.
IEEE J Biomed Health Inform ; 26(6): 2458-2468, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35452393

RESUMO

Despite efforts made to model and predict COVID-19 transmission, large predictive uncertainty remains. Failure to understand the dynamics of the nonlinear pandemic prediction model is an important reason. To this end, local and multiple global sensitivity analysis approaches are synthetically applied to analyze the sensitivities of parameters and initial state variables and community size (N) in susceptible-infected-recovered (SIR) and its variant susceptible-exposed-infected-recovered (SEIR) models and basic reproduction number (R0), aiming to provide prior information for parameter estimation and suggestions for COVID-19 prevention and control measures. We found that N influences both the maximum number of actively infected cases and the date on which the maximum number of actively infected cases is reached. The high effect of N on maximum actively infected cases and peak date suggests the necessity of isolating the infected cases in a small community. The protection rate and average quarantined time are most sensitive to the infected populations, with a summation of their first-order sensitivity indices greater than 0.585, and their interactions are also substantial, being 0.389 and 0.334, respectively. The high sensitivities and interaction between the protection rate and average quarantined time suggest that protection and isolation measures should always be implemented in conjunction and started as early as possible. These findings provide insights into the predictability of the pandemic models by estimating influential parameters and suggest how to effectively prevent and control epidemic transmission.


Assuntos
COVID-19 , Pandemias , Número Básico de Reprodução , COVID-19/epidemiologia , Humanos , Quarentena , SARS-CoV-2
12.
Adv Sci (Weinh) ; 9(14): e2200268, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35274481

RESUMO

Hard yet flexible coatings with multi-functionalities are useful for foldable displays and marine industries but rare. In this study, a highly cross-linked multifunctional hybrid coating with ceramic-like hardness and polymer-like flexibility is reported. The coating is prepared via a step-by-step strategy, where two types of epoxy-oligosiloxane nanoclusters are first synthesized by sol-gel chemistry, and amine-terminated curing agents are used to cross-link them at room temperature. The coating is highly transparent (>92% transmittance), hard (6-7H), and flexible (10 mm bending diameter) because of the unique combination of siloxane nanoclusters and polymer networks. Meanwhile, since the coating contains fouling-resistant telomer and low-surface-tension liquid lubricant polydimethylsiloxane (PDMS), it exhibits excellent anti-biofouling and self-cleaning properties. The results indicate that the mechanical and antifouling properties of the coating can be easily tuned and prove that the step-by-step strategy is a promising and universal method. The novel coatings can meet the needs of applications in foldable displays, marine industries, and other fields.

13.
Epidemiol Infect ; 150: e46, 2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-35067231

RESUMO

As a result of the COVID-19 pandemic, whether and when the world can reach herd immunity and return to normal life and a strategy for accelerating vaccination programmes constitute major concerns. We employed Metropolis-Hastings sampling and an epidemic model to design experiments based on the current vaccinations administered and a more equitable vaccine allocation scenario. The results show that most high-income countries can reach herd immunity in less than 1 year, whereas low-income countries should reach this state after more than 3 years. With a more equitable vaccine allocation strategy, global herd immunity can be reached in 2021. However, the spread of SARS-CoV-2 variants means that an additional 83 days will be needed to reach global herd immunity and that the number of cumulative cases will increase by 113.37% in 2021. With the more equitable vaccine allocation scenario, the number of cumulative cases will increase by only 5.70% without additional vaccine doses. As SARS-CoV-2 variants arise, herd immunity could be delayed to the point that a return to normal life is theoretically impossible in 2021. Nevertheless, a more equitable global vaccine allocation strategy, such as providing rapid vaccine assistance to low-income countries/regions, can improve the prevention of COVID-19 infection even though the virus could mutate.


Assuntos
Vacinas contra COVID-19/administração & dosagem , COVID-19/prevenção & controle , Modelos Epidemiológicos , Imunidade Coletiva , SARS-CoV-2/imunologia , Países Desenvolvidos , Países em Desenvolvimento , Saúde Global , Equidade em Saúde , Humanos , Cooperação Internacional , Alocação de Recursos
14.
Sci Total Environ ; 821: 153481, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35093363

RESUMO

Integrating the economic values of ecosystem services provided by different land uses into decision analysis is critical to achieving effective environmental management in endorheic basins. However, policymaking often ignores the uncertainty related to the variability of parameters in ecosystem service values. To this end, we identified sensitive parameters in the ecosystem service values under four land uses using the global sensitivity analysis method and quantified the potential monetary outcomes based on the Monte Carlo method. The results indicated that only a few sensitive parameters, such as water yield (Qi) and treatment costs per unit of nitrogen (Cost_N), were the primary sources of uncertainty. Therefore, we suggest that improving the precision of sensitive parameters is essential for reducing uncertainty in the total ecosystem service value. Additionally, the overall monetary outcomes for cropland exhibited negative values and had higher risk and lower benefits than those for forest from the standpoint of ecosystem services. In addition, the nonmarketed service of landscape aesthetic made the monetary outcomes of water bodies higher than those of cropland, yet the value of landscape aesthetic was highly uncertain. Therefore, efforts should be made to improve total monetary outcomes by decreasing the negative values in food provisioning of cropland and the uncertainty in landscape aesthetic for water bodies. The sensitivity analysis and uncertainty analysis provide important guidelines for quantifying and reducing the related uncertainty and provide policy information for environmental management based on a comprehensive consideration of the potential ecosystem service values for various land uses.


Assuntos
Ecossistema , Rios , China , Conservação dos Recursos Naturais , Incerteza
15.
Healthcare (Basel) ; 9(10)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34682973

RESUMO

The ongoing spread of coronavirus disease 2019 (COVID-19) in most South and Southeast Asian countries has led to severe health and economic impacts. Evaluating the performance of nonpharmaceutical interventions in reducing the number of daily new cases is essential for policy designs. Analysis of the growth rate of daily new cases indicates that the value (5.47%) decreased significantly after nonpharmaceutical interventions were adopted (1.85%). Vaccinations failed to significantly reduce the growth rates, which were 0.67% before vaccination and 2.44% and 2.05% after 14 and 28 d of vaccination, respectively. Stringent nonpharmaceutical interventions have been loosened after vaccination drives in most countries. To predict the spread of COVID-19 and clarify the implications to adjust nonpharmaceutical interventions, we build a susceptible-infected-recovered-vaccinated (SIRV) model with a nonpharmaceutical intervention module and Metropolis-Hastings sampling in three scenarios (optimistic, neutral, and pessimistic). The daily new cases are expected to decrease rapidly or increase with a flatter curve with stronger nonpharmaceutical interventions, and the peak date is expected to occur earlier (5-20 d) with minimum infections. These findings demonstrate that adopting stringent nonpharmaceutical interventions is the key to alleviating the spread of COVID-19 before attaining worldwide herd immunity.

16.
iScience ; 24(10): 103197, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34712914

RESUMO

Superhydrophobic coatings have tremendous potential for protecting porous structures from corrosion. However, the weak adhesion and poor abrasion resistance have long been challenges for their real-life applications. Inspired by tree roots, we prepared a robust superhydrophobic coating by spraying fluorinated nanodiamonds (FNDs) on a permeable epoxy coating. The epoxy can not only coat the surface but also permeate deeply inside a porous substrate and consolidate in situ as tree roots in soil. Thus, the structure is thoroughly reinforced where the pull-off strength reaches 9.4 MPa for concrete. On the other hand, the surface is covered with immobilized FNDs, forming a superhydrophobic surface. Thanks to the ultra-hard FNDs, the coating surface has high abrasion resistance and its superhydrophobicity holds even after 100 abrasion cycles. Moreover, it exhibits self-cleaning, anti-icing, and anticorrosion performance. It is promising in protecting various porous structures such as concrete, wood, and untreated corroded steel.

17.
Mar Drugs ; 19(9)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34564143

RESUMO

Butenolide derivatives have the potential to be effective and environmentally friendly antifouling agents. In the present study, a butenolide derivative was structurally modified into Boc-butenolide to increase its melting point and remove its foul smell. The structurally modified Boc-butenolide demonstrated similar antifouling capabilities to butenolide in larval settlement bioassays but with significantly lower toxicity at high concentrations. Release-rate measurements demonstrated that the antifouling compound Boc-butenolide could be released from polycaprolactone-polyurethane (PCL-PU)-based coatings to inhibit the attachment of foulers. The coating matrix was easily degraded in the marine environment. The performance of the Boc-butenolide antifouling coatings was further examined through a marine field test. The coverage of biofouler on the Boc-butenolide coatings was low after 2 months, indicating the antifouling potential of Boc-butenolide.


Assuntos
4-Butirolactona/análogos & derivados , Incrustação Biológica/prevenção & controle , Carbamatos/farmacologia , Poliésteres/farmacologia , Poliuretanos/farmacologia , 4-Butirolactona/química , 4-Butirolactona/farmacologia , Animais , Carbamatos/química , Larva , Pintura , Poliquetos , Poliésteres/química , Poliuretanos/química , Thoracica
18.
Langmuir ; 37(27): 8253-8260, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34190560

RESUMO

Silicone elastomer-based fouling release coatings have been gaining increased attention in marine antibiofouling. However, the lack of fouling resistance limits their application. Introducing a zwitterionic polymer into silicone enhances its fouling resistance, but their incompatibility makes this challenging. In this work, a silicone elastomer with zwitterionic pendant chains has been prepared by grafting a telomer of tertiary carboxybetaine dodecafluoroheptyl ester ethyl acrylate (TCBF) and 3-mercaptopropyltriethoxysilane to the bis-silanol-terminated poly(dimethylsiloxane) (PDMS). The fluorocarbon groups drive the telomer onto the surface in the film formation process, while the TCBF groups hydrolyze and generate zwitterions on the surface, which is confirmed by attenuated total reflection infrared spectra analysis and water contact angle measurements. Bioassays using marine bacteria (Pseudomonas sp.) and diatoms (Navicula incerta) demonstrate that the antifouling efficacy is improved as the telomer content increases. The bacteria and diatom adhesion decreases by 95 and 81%, respectively, for the PDMS with 30 wt % telomer compared with the unmodified PDMS control. Meanwhile, the fouling release performance of PDMS is maintained with a pseudobarnacle removal strength of ∼0.1 MPa. This work provides a facile way to fabricate efficient silicone-based antifouling coatings.


Assuntos
Incrustação Biológica , Diatomáceas , Incrustação Biológica/prevenção & controle , Polímeros , Pseudomonas , Elastômeros de Silicone , Propriedades de Superfície
19.
ACS Appl Mater Interfaces ; 13(11): 13735-13743, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33710850

RESUMO

Traditional antifouling coatings are generally based on a single antifouling mechanism, which can hardly meet the needs of different occasions. Here, a single "kill-resist-renew trinity" polymeric coating integrating fouling killing, resistance, and releasing functions is reported. To achieve the design, a novel monomer-tertiary carboxybetaine ester acrylate with the antifouling group N-(2,4,6-trichlorophenyl)maleimide (TCB-TCPM) is synthesized and copolymerized with methacrylic anhydride via reversible addition-fragmentation chain transfer polymerization yielding a degradable hyperbranched polymer. Such a polymer at the surface/seawater is able to hydrolyze and degrade to short segments forming a dynamic surface (releasing). The hydrolysis of TCB-TCPM generates the antifouling groups TCPM (killing) and zwitterionic groups (resistance). Such a polymeric coating exhibits a controllable degradation rate, which increases with the degrees of branching. The antibacterial assay demonstrates that the antifouling ability arise from the synergistic effect of "attacking" and "defending". This study provides a new strategy to solve the challenging problem of marine biofouling.


Assuntos
Incrustação Biológica/prevenção & controle , Maleimidas/química , Polímeros/química , Anidridos/química , Halogenação , Polimerização , Propriedades de Superfície
20.
J Mater Chem B ; 9(5): 1384-1394, 2021 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-33459744

RESUMO

Silicone elastomer coatings have attracted increasing attention owing to their eco-friendly nature, excellent fouling release ability and drag-reducing property. However, the poor mechanical properties and lack of fouling resistance limit their applications. Herein, a silicone-based polyurethane with 2-ureido-4[1H]-pyrimidinone (UPy) and amphiphilic pendant chains is reported. The UPy groups and urethane can form hydrogen bonds with various substrates so that the coating has significantly improved adhesion strength (0.9-3.0 MPa) compared with the PDMS elastomer (0.3-0.4 MPa). Moreover, the quadruple hydrogen bonding between UPy moieties allows the polymer to have excellent self-healing ability and high elasticity. The modified polymeric coating has low surface energy (24 mJ m-2) and low elastic modulus (1.9 MPa), so it exhibits good fouling release performance. Besides, the amphiphilic side chains can effectively resist protein adsorption and adhesion of the marine bacteria Pseudomonas sp. and diatom Navicula incerta. The novel design can improve the resistance of silicone coating to biofouling and mechanical forces and is promising for high-performance antifouling coatings.


Assuntos
Poliuretanos/química , Silicones/química , Animais , Incrustação Biológica , Peixes , Propriedades de Superfície
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