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Acid corrosion protection data for POM-ILs 1 and 2.
Source publication
Corrosion of stone by acid rain and deterioration from biofilms are global problems for industrial and residential buildings as well as cultural heritage such as statues or historic buildings. Here we show how typical building stones can be protected from corrosion (“weathering”) and biofilm formation (“biodeterioration”) by application of thin fil...
Contexts in source publication
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... coating studies showed that brush coating resulted in homogeneous surface coverage whereas other methods (dip- coating, spray-coating) displayed less homogeneous POM-IL distribution. Figure 2. Acid vapour corrosion protection of POM-IL-coated stone samples, studied by exposing the samples to acetic acid vapour for 72 h; for weight losses see Table 3. RO: Romery stone; BB: Belgian Bluestone; DO: Dom stone. ...
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... contrast, the Dom samples coated with 1 or 2 both show only minor corrosion and structural integrity of the stone samples is retained (Fig 2). When analyzing the weight losses observed for the acid vapor tests (Table 3), both POM-ILs show significant ...
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... mg POM-IL coating per sample) showed only small increases in the amount of corrosion observed. This emphasizes that tuning of film thickness and coating procedure can be used to achieve high acid corrosion resistance even at low POM-IL loading (Table 3). Next, we examined the integrity of the POM-IL coatings by exposing the coated stones to simulated acid rain. ...
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... this end, the samples were sprayed continuously with aqueous acetic acid (20 wt-%) for a period of 3 h at a flow rate of ~60 mL min -1 , see SI. After the acid rain treatment, the samples were recovered, rinsed with water and acetone, oven-dried (120 o C for 1 h) and the weight loss was determined, see Table 3. The acid rain tests show corrosion protection effects similar to the vapor chamber study, while the corrosion observed is overall higher due to the harsh mechanical and chemical treatment: both POM-ILs result in significantly reduced acid corrosion. ...
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... weight loss) for POM-IL 1 compared with POM-IL 2. The acid rain simulator study further highlights the POM-IL coating durability, enabling the coating to retain its structural integrity even under harsh spraying conditions. Table 3. RO: Romery stone; BB: Belgian Bluestone; DO: Dom stone. ...
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Citations
... [26][27][28] Since both POMs and polypeptides have each been shown to exhibit potent antimicrobial properties, it therefore follows that hybrid materials based on these components emerge as interesting candidates to overcome the increasing problem of bacterial resistance towards conventional antibiotics. [29][30][31][32] The ionic combination of peptides or peptide-polymers and POMs have resulted in hybrids with better antimicrobial activities than each component alone. [33][34][35] In addition, the vast combinatorial possibilities of both POMs and amino acids means that it is also possible to tune the secondary structure, molecular weight and antimicrobial properties of the hybrid. ...
... In the case of POMlymers, precipitation in water offered the advantage that TBA cations could be removed almost completely, which was crucial in order to perfectly isolate the contributions of the POM against bacteria, since tetraalkylammonium cations are known antibacterial agents. [29] After polymerisation, the composition of the polymeric scaffold was evaluated using 1 H-NMR on the POMlymers precipitated in diethyl ether ( Figure 2 and S8-S10). The ratio between the comonomers reflected that of the reaction mixture as calculated from the integration of the proton signals of the trifluoroacetamide and the benzylic hydrogens of the Z protecting group (Figure 2). ...
The ring‐opening polymerisation of α‐amino acid N‐carboxyanhydrides (NCAs) offers a simple and scalable route to polypeptides with predicted and narrow molecular weight distributions. Here we show how polyoxometalates (POMs)—redox‐active molecular metal‐oxide anions—can serve as inorganic scaffold initiators for such NCA polymerisations. This “On‐POM polymerisation” strategy serves as an innovative platform to design hybrid materials with additive or synergistic properties stemming from the inorganic and polypeptide component parts. We have used this synthetic approach to synthesise a library of bactericidal poly(lysine)–POM hybrid derivatives that can be used to prevent biofilm formation. This versatile “On‐POM polymerisation” method provides a flexible synthetic approach for combining inorganic scaffolds with amino acids, and the potential to tailor and improve the specificity and performance of hybrid antimicrobial materials.
... [26][27][28] Since both POMs and polypeptides have each been shown to exhibit potent antimicrobial properties, it therefore follows that hybrid materials based on these components emerge as interesting candidates to overcome the increasing problem of bacterial resistance towards conventional antibiotics. [29][30][31][32] The ionic combination of peptides or peptide-polymers and POMs have resulted in hybrids with better antimicrobial activities than each component alone. [33][34][35] In addition, the vast combinatorial possibilities of both POMs and amino acids means that it is also possible to tune the secondary structure, molecular weight and antimicrobial properties of the hybrid. ...
... In the case of POMlymers, precipitation in water offered the advantage that TBA cations could be removed almost completely, which was crucial in order to perfectly isolate the contributions of the POM against bacteria, since tetraalkylammonium cations are known antibacterial agents. [29] After polymerisation, the composition of the polymeric scaffold was evaluated using 1 H-NMR on the POMlymers precipitated in diethyl ether ( Figure 2 and S8-S10). The ratio between the comonomers reflected that of the reaction mixture as calculated from the integration of the proton signals of the trifluoroacetamide and the benzylic hydrogens of the Z protecting group (Figure 2). ...
On‐POM polymerisation: An amino‐functionalised polyoxometalate (POM) acts as initiator for the ring‐opening polymerisation (ROP) of α‐amino acid N‐carboxyanhydrides (NCAs) under living polymerisation conditions. The resulting POM–peptide materials (POMlymers) possess bactericidal properties and prevent biofilm formation.
Abstract
The ring‐opening polymerisation of α‐amino acid N‐carboxyanhydrides (NCAs) offers a simple and scalable route to polypeptides with predicted and narrow molecular weight distributions. Here we show how polyoxometalates (POMs)—redox‐active molecular metal‐oxide anions—can serve as inorganic scaffold initiators for such NCA polymerisations. This “On‐POM polymerisation” strategy serves as an innovative platform to design hybrid materials with additive or synergistic properties stemming from the inorganic and polypeptide component parts. We have used this synthetic approach to synthesise a library of bactericidal poly(lysine)–POM hybrid derivatives that can be used to prevent biofilm formation. This versatile “On‐POM polymerisation” method provides a flexible synthetic approach for combining inorganic scaffolds with amino acids, and the potential to tailor and improve the specificity and performance of hybrid antimicrobial materials.
... TheP OM-IL is synthesized as described in the literature [10,12,24,25] by combination of the lacunary-Keggin cluster anion ([a-SiW 11 O 39 ] 8À ) [26] and the antimicrobial tetra-n-heptyl ammonium cation (Q 7 (= (n-C 7 H 15 ) 4 N + ) [27] (Figure 1). The magPOM-SILPs were prepared by dispersing SiO 2 @Fe 3 O 4 particles (4.0 g) in aP OM-IL solution in acetone (50 mL, [POM-IL] = 3.36 mm, m(POM-IL = 1.0 g) and subsequent vacuum drying, giving the composite magPOM-SILP 2 with aP OM-IL loading of 20 wt %, see Supporting Information for details.A saresult of the partial filling of the pores in 2 with the POM-IL, the BET specific surface area of 2 was reduced to around 100 m 2 g À1 and the BJH pore volume was 0.70 cm 3 g À1 ;for further characterization details,see Support-ing Information. ...
... In sum, PS microplastics removal by magnetic particle attachment could provide ameans of treating larger volumes of water which are not amenable to classical filtration. [21] Some of our previous research has confirmed the bactericidal properties of POM-ILs, [10,12,25] therefore we hypothesized that magPOM-SILP 2 would be able to purify water heavily contaminated with bacteria. Thea ntibacterial water purification properties of the magPOM-SILPs were tested against gram-negative E. coli and gram-positive B. subtilis. ...
Filtration is an established water‐purification technology. However, due to low flow rates, the filtration of large volumes of water is often not practical. Herein, we report an alternative purification approach in which a magnetic nanoparticle composite is used to remove organic, inorganic, microbial, and microplastics pollutants from water. The composite is based on a polyoxometalate ionic liquid (POM‐IL) adsorbed onto magnetic microporous core–shell Fe2O3/SiO2 particles, giving a magnetic POM‐supported ionic liquid phase (magPOM‐SILP). Efficient, often quantitative removal of several typical surface water pollutants is reported together with facile removal of the particles using a permanent magnet. Tuning of the composite components could lead to new materials for centralized and decentralized water purification systems.
... More recently, Streb and co-workers have prepared POM-ILs from lacunary Keggin derivatives including [SiW 11 O 39 ] 8À and [a-PW 9 O 34 ] 9À and simple QAAs, predominantly tetrahexyl-, tetraheptyl-, tetraoctyl-, and trihexyl(tetradecyl)-ammonium cations. [25,[118][119][120] Their targeted applications included water filtration and treatment, [118,120] and anticorrosive/antibacterial coatings for metals and building stone. [25,119] In these applications, both components of the POM-IL were engaged in the application. ...
... [25,[118][119][120] Their targeted applications included water filtration and treatment, [118,120] and anticorrosive/antibacterial coatings for metals and building stone. [25,119] In these applications, both components of the POM-IL were engaged in the application. Lacunary POMs which feature accessible metal cation binding sites, served to remove heavy metal contaminants in water treatment, while the organic cation attracts organic contaminants by hydrophobic interactions. ...
Polyoxometalates (POMs) are molecular metal‐oxide anions applied in energy conversion and storage, manipulation of biomolecules, catalysis, as well as materials design and assembly. Although often overlooked, the interplay of intrinsically anionic POMs with organic and inorganic cations is crucial to control POM self‐assembly, stabilization, solubility, and function. Beyond simple alkali metals and ammonium, chemically diverse cations including dendrimers, polyvalent metals, metal complexes, amphiphiles, and alkaloids allow tailoring properties for known applications, and those yet to be discovered. This review provides an overview of fundamental POM–cation interactions in solution, the resulting solid‐state compounds, and behavior and properties that emerge from these POM–cation interactions. We will explore how application‐inspired research has exploited cation‐controlled design to discover new POM materials, which in turn has led to the quest for fundamental understanding of POM–cation interactions.
Supramolecular polymers (SPs) exhibit intriguing benefits in functional soft materials due to their dynamic bonding feature. However, most SPs can only exist in the solution state and fail to form bulk materials, which limits their applications. Here, we report the fabrication of semi‐solid bulk SP materials by using polyoxometalate (POM) nanoclusters as supramolecular cross‐linkers to solidify a deep eutectic solvent (DES). The abundant protons and strong hydrogen bonds afforded by POMs enable these SP materials as superprotonic conductive electrolytes with sufficient mechanical strength, showing a proton conductivity more than 1×10 ‐4 S cm ‐1 and a breaking strength exceeding 1 MPa at room temperature. Moreover, the thermodynamic reversibility of the SP electrolytes allows them to form a stable electrode‐electrolyte interface by a facile melt‐infiltration strategy upon mild heating, which leads to improved performance in supercapacitors. This work presents an innovative DES/POM hybrid system as a promising platform to develop functional supramolecular materials for energy and electronic applications.
Supramolecular polymers (SPs) exhibit intriguing benefits in functional soft materials due to their dynamic bonding feature. However, most SPs can only exist in the solution state and fail to form bulk materials, which limits their applications. Here, we report the fabrication of semi‐solid bulk SP materials by using polyoxometalate (POM) nanoclusters as supramolecular cross‐linkers to solidify a deep eutectic solvent (DES). The abundant protons and strong hydrogen bonds afforded by POMs enable these SP materials as superprotonic conductive electrolytes with sufficient mechanical strength, showing a proton conductivity more than 1×10⁻⁴ S cm⁻¹ and a breaking strength exceeding 1 MPa at room temperature. Moreover, the thermodynamic reversibility of the SP electrolytes allows them to form a stable electrode‐electrolyte interface by a facile melt‐infiltration strategy upon mild heating, which leads to improved performance in supercapacitors. This work presents an innovative DES/POM hybrid system as a promising platform to develop functional supramolecular materials for energy and electronic applications.
Widespread use of plastics poses a serious environmental hazard to our planet and should be substituted by eco-friendly and biodegradable alternatives, simultaneously reducing waste of perishable food products and the risk of transmission of pathogenic microbes. In our study, we describe how the water solubility of the antimicrobial surfactant ethyl lauroyl arginate (LAE) can be reduced through complexation with a Keggin-type polyoxometalate (POM), K8[SiW11O39]. The POM-LAE complex, LAE7K[SiW11O39], was effective against Listeria monocytogenes (L. monocytogenes) and Escherichia coli (E. coli) with minimal inhibitory concentrations (MICs) of 32 and 64 μg/mL, respectively, with the important finding that the concentrations of LAE required to inhibit bacterial growth were as much as two times lower in the POM-LAE complex, compared with LAE on its own. In addition, our results demonstrate that POM-LAE is both an effective inhibitor of biofilm formation and is also able to destroy pre-formed biofilms of L. monocytogenes and E. coli at MIC concentrations. Further, POM-LAE was incorporated into carboxymethyl cellulose (CMC) films that were able to reduce 7–8 log (CFU/mL) of L. monocytogenes at concentrations of 5–10% POM-LAE. In vivo assays of the POM-LAE-CMC films with cured ham prevented initialk bacterial growth with a 0.77 log significative reduction in bacterial counts. Overall, this work provides new alternatives for the development of antimicrobial biodegradable films for ready-to-eat (RTE) foods prone to contamination with pathogenic bacteria, such as L. monocytogenes, while also circumventing practical issues related to the incorporation of LAE into active packaging films.
The energetically viable fabrication of stable and highly efficient solid acid catalysts is one of the key steps in large‐scale transformation processes of biomass resources. Herein, the covalent modification of the classical Dawson polyoxometalate (POMs) with sulfonic acids (‐SO3H) is reported by grafting sulfonic acid groups on the POM's surface followed by oxidation of (3‐mercaptopropyl)trimethoxysilane. The acidity of TBA6‐P2W17‐SO3H (TBA=tetrabutyl ammonium) has been demonstrated by using ³¹P NMR spectroscopy, clearly indicating the presence of strong Brønsted acid sites. The presence of TBA counterions renders the solid acid catalyst as a promising candidate for phase transfer catalytic processes. The TBA6‐P2W17‐SO3H shows remarkable activity and selectivity, excellent stability, and great substrate compatibility for the esterification of free fatty acids (FFA) with methanol and conversion into biodiesel at 70 °C with >98 % conversion of oleic acid in 20 min. The excellent catalytic performance can be attributed to the formation of a catalytically active emulsion, which results in a uniform catalytic behavior during the reaction, leading to efficient interaction between the substrate and the active sites of the catalyst. Most importantly, the catalyst can be easily recovered and reused without any loss of its catalytic activity owing to its excellent phase transfer properties. This work offers an efficient and cost‐effective strategy for large‐scale biomass conversion applications.
Polyoxometalate (POM) compounds constitute a wide family rich of more than several thousand inorganic compounds which can be finely tuned at the molecular level. Considering the high diversity in their structures and properties, the incorporation of such inorganic components into liquid crystalline phases or ionic liquid phases is particularly relevant for the elaboration of functional materials. By adjusting the molecular structures of the anions and the nature of the counter cations, many authors designed different types of mesophases sometimes with application in optoelectronics, or true POM‐based ionic liquids (POM‐ILs with melting temperatures below 100 °C). The latter turn out to be highly interesting for various applications in catalysis, depollution, or protection of the historical heritage. This review focuses on the recent developments in these organic/inorganic hybrid materials, POM‐based ionic liquid crystals and POM‐ILs, and their applications.
Nicht nur sauber, sondern rein: Ein Dreikomponentenkomposit für die magnetische Entfernung organischer, anorganischer, mikrobieller und Mikroplastik‐Verunreinigungen aus Wasser wird vorgestellt. Magnetische Fe2O3/SiO2‐Kern‐Schale‐Nanopartikel werden mit einer Polyoxometallat‐ionischen Flüssigkeit beschichtet. Das Komposit kann in Wasser dispergiert werden, bindet multiple Verunreinigungen und kann durch einen Permanentmagneten entfernt werden.
Abstract
Filtration ist eine etablierte Wasserreinigungstechnologie. Aufgrund der niedrigen Durchflussraten ist jedoch die Reinigung großer Wassermengen meist unpraktisch. Hier berichten wir über einen alternativen Reinigungsprozess, bei dem magnetische Nanopartikel‐Komposite genutzt werden, um organische, anorganische, mikrobielle und Mikroplastik‐Vernunreinigungen aus Wasser zu entfernen. Das Komposit besteht aus einer Polyoxometallat‐ionischen Flüssigkeit (POM‐IL), die auf magnetische, mikroporöse Kern‐Schale‐Fe2O3‐SiO2‐Partikel adsorbiert wurde, um eine magnetische POM‐unterstützte ionische Flüssigphase (magPOM‐SILP) zu bilden. Die effiziente, häufig quantiative Entfernung verschiedener Oberflächenwasser‐Schadstoffe sowie die einfache Rückgewinnung der Partikel durch einen Permanentmagneten wird beschrieben. Die Feinabstimmung der Kompositbestandteile könnte zu neuen Materialien für zentrale und dezentrale Wasseraufreinigung führen.
