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Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands.
In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1–10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles.
In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced.
Laser-induced periodic surface structures (LIPSS, ripples) with ~500–700 nm period were produced on titanium alloy (Ti6Al4V) surfaces upon scan processing in air by a Ti:sapphire femtosecond laser. The tribological performance of the surfaces were qualified in linear reciprocating sliding tribological tests against balls made of different materials using different oilbased lubricants. Extending our previous work, we studied the admixture of the additive 2-ethylhexyl-zinc-dithiophosphate to a base oil containing only anti-oxidants and temperature stabilizers. The presence of this additive along with the variation of the chemical composition of the counterbodies allows us to explore the synergy of the additive with the laseroxidized nanostructures.
In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature.
The influence of processing parameters on X‑ray emission during ultra‑short pulse laser machining
(2019)
During ultra-short laser material processing at high laser pulse repetition rates unwanted X-ray radiation can be generated in a quantity that may constitute a potential risk for health. An adequate X-ray radiation protection requires a thoroughly understanding of the influence of the laser processing parameters on the generation of X-ray radiation. In the present work, the generated X-ray dose during laser machining was investigated in air for varying beam scanning conditions at a pulse duration of 925 fs, a center wavelength of 1030 nm and a laser peak intensity of 2.6 × 10^14 W/cm^2. The X-ray radiation dose and the corresponding spectral X-ray emission were investigated in dependence on the laser’s pulse repetition rate and on the beam scanning speed. The results show a strong dependence of the X-ray emission on these laser processing parameters.
Understanding the interaction between nanoparticles and the matrix and the properties of interphase is crucial to predict the macroscopic properties of a nanocomposite system. Here, we investigate the interaction between boehmite nanoparticles (BNPs) and epoxy using different atomic force microscopy (AFM) approaches. We demonstrate benefits of using multifrequency intermodulation AFM (ImAFM) to obtain information about conservative, dissipative and van der Waals tip-surface forces and probing local properties of nanoparticles, matrix and the interphase.
We utilize scanning kelvin probe microscopy (SKPM) to probe surface potential as a tool to visualize material contrast with a physical parameter, which is independent from the mechanics of the surface. Combining the information from ImAFM stiffness and SKPM surface potential results in a precise characterization of interfacial region, demonstrating that the interphase is softer than epoxy and boehmite nanoparticles. Further, we investigated the effect of boehmite nanoparticles on the bulk properties of epoxy matrix. ImAFM stiffness maps revealed the significant stiffening effect of boehmite nanoparticles on anhydride-cured epoxy matrix. The energy Dissipation of epoxy Matrix locally measured by ImAFM shows a considerable increase compared to that of neat epoxy. These measurements suggest a substantial alteration of epoxy structure induced by the presence of boehmite.
We show that complex physical and chemical interactions between boehmite nanoparticles and epoxy drastically affect matrix properties, which in the future will provide tuning of material properties for further optimization in applications from automotive to aerospace. We utilize intermodulation atomic force microscopy (ImAFM) for probing local stiffness of both particles and polymer matrix. Stiff particles are expected to increase total stiffness of nanocomposites and the stiffness of polymer should remain unchanged. However, ImAFM revealed that stiffness of matrix in epoxy/boehmite nanocomposite is significantly higher than unfilled epoxy. The stiffening effect of the boehmite on epoxy also depends on the particle concentration. To understand the mechanism behind property alteration induced by boehmite nanoparticles, network architecture is investigated using dynamic mechanical thermal analysis (DMTA). It was revealed that although with 15 wt% boehmite nanoparticles the modulus at glassy state increases, crosslinking density of epoxy for this composition is drastically low.
Understanding the correlation between the morphological and functional properties of particulate materials is crucial across all fields of physical and natural sciences. This manuscript reports on the investigation of the effect of polyethylene glycol (PEG) employed as a capping Agent in the synthesis of SrTiO3 crystals. The crucial influence of PEG on both the shape and size of the strontium titanate particles is revealed, highlighting the effect on the photocurrents measured under
UV–Vis irradiation.
Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
The present study reports on results of analysis of the elemental composition of thin films by electron probe microanalysis with energy dispersive (ED-EPMA) X-ray spectrometry in conjunction with the dedicated thin-film analysis software package Stratagem and by X-ray fluorescence in its version with a micro-focus X-ray fluorescence (μ-XRF) source attached to a scanning electron microscope (SEM). Two thin-film systems have been analyzed: Fe1-xNix on silicon wafer and Si1-xGex on Al2O3 substrate, in both cases the layers being grown to a thickness of about 200 nm by ion beam sputter deposition. Samples of five different atomic fractions have been produced and analyzed for each thin-film system. Moreover, reference samples with certified elemental composition and thickness have been also available. This study is part of an interlaboratory comparison organized in the frame of standardization technical committee ISO/TC 201 “Surface chemical analysis.” Two laboratories have been analyzed by ED-EPMA (one laboratory standardless and one laboratory using both standardless and with standards variants) and one laboratory by μ-XRF (standardless and with standards). All the elemental compositions obtained with different methods are in very good agreement for the complete two sets of five samples each.
Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment.
The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
Identifying nanomaterials (NMs) according to European Union Legislation is challenging, as there is an enormous variety of materials, with different physico-chemical properties. The NanoDefiner Framework and its Decision Support Flow Scheme (DSFS) allow choosing the optimal method to measure the particle size distribution by matching the material properties and the performance of the particular measurement techniques. The DSFS leads to a reliable and economic decision whether a material is an NM or not based on scientific criteria and respecting regulatory requirements. The DSFS starts beyond regulatory requirements by identifying non-NMs by a proxy Approach based on their volume-specific surface area. In a second step, it identifies NMs. The DSFS is tested on real-world materials and is implemented in an e-tool. The DSFS is compared with a decision flowchart of the European Commission’s (EC) Joint Research Centre (JRC), which rigorously follows the explicit criteria of the EC NM definition with the focus on identifying NMs, and non-NMs are identified by exclusion. The two approaches build on the same scientific basis and measurement methods, but start from opposite ends: the JRC Flowchart starts by identifying NMs, whereas the NanoDefiner Framework first identifies non-NMs.
Most real core-shell nanoparticle (CSNP) samples deviate from an ideal core-shell structure potentially having significant impact on the particle properties. An ideal structure displays a spherical core fully encapsulated by a shell of homogeneous thickness, and all particles in the sample exhibit the same shell thickness. Therefore,
analytical techniques are required that can identify and characterize such deviations.
This study demonstrates that by analysis of the inelastic background in X-ray photoelectron spectroscopy (XPS) survey spectra, the following types of deviations can be identified and quantified: the nonuniformity of the shell thickness within a nanoparticle sample and the incomplete encapsulation of the cores by the shell material. Furthermore, CSNP shell thicknesses and relative coverages can be obtained. These results allow for a quick and straightforward comparison between several batches of a specific CSNP, different coating approaches, and so forth. The presented XPS methodology requires a submonolayer distribution of CSNPs on a substrate.
Poly(tetrafluoroethylene)-poly(methyl methacrylate) and poly(tetrafluoroethylene)-polystyrene polymer CSNPs serve as model systems to demonstrate the applicability of the approach.
Three binary fcc-structured alloys (fcc–Ir0.50Pt0.50, fcc Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50) were 14 prepared from [Ir(NH3)5Cl][PtCl6], [Ir(NH3)5Cl][PtBr6], [Rh(NH3)5Cl]2[PtCl6]Cl2 and 15 [Rh(NH3)5Cl][PdCl4]·H2O, respectively, as single-source precursors. All alloys were prepared by 16 thermal decomposition in gaseous hydrogen flow below 800 °C. Fcc–Ir0.50Pt0.50 and fcc–Rh0.50Pd0.50 17 correspond to miscibility gaps on binary metallic phase diagrams and can be considered as 18 metastable alloys. Detailed comparison of [Ir(NH3)5Cl][PtCl6] and [Ir(NH3)5Cl][PtBr6] crystal 19 structures suggests that two isoformular salts are not isostructural. In [Ir(NH3)5Cl][PtBr6], specific 20 Br…Br interactions are responsible for crystal structure arrangement. Room temperature 21 compressibility of fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50 has been investigated up to 50 GPa 22 in diamond anvil cells. All investigated fcc-structured binary alloys are stable under compression. 23 Atomic volumes and bulk moduli show good agreement with ideal solutions model. For fcc–24 Ir0.50Pt0.50, V0/Z = 14.597(6) Å3·atom-1, B0 = 321(6) GPa, B0' = 6(1); for fcc–Rh0.66Pt0.33, V0/Z = 14.211(3) 25 Å3·atom-1, B0 =259(1) GPa, B0' = 6.66(9); for fcc–Rh0.50Pd0.50, V0/Z = 14.18(2) Å3·atom-1, B0 =223(4) GPa, 26 B0' = 5.0(3).
The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800◦C. Above 600◦C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500°C and is completely oxidized above 700°C.
Rhodium(III) octahedral complexes with amine and chloride ligands are the most common starting compounds for preparing catalytically active rhodium(I) and rhodium(III) species. Despite intensive study during the last 100 years, synthesis and crystal structures of rhodium(III) complexes were described only briefly. Some [RhClx(NH3)6-x] compounds are still unknown. In this study, available information about synthetic protocols and the crystal structures of possible [RhClx(NH3)6−x] octahedral species are summarized and critically analyzed. Unknown crystal structuresof(NH4)2[Rh(NH3)Cl5],trans–[Rh(NH3)4Cl2]Cl·H2O,andcis–[Rh(NH3)4Cl2]Clarereported based on high quality single crystal X-ray diffraction data. The crystal structure of [Rh(NH3)5Cl]Cl2 was redetermined. All available crystal structures with octahedral complexes [RhClx(NH3)6-x] were analyzed in terms of their packings and pseudo-translational sublattices. Pseudo-translation lattices suggest face-centered cubic and hexagonal closed-packed sub-cells, where Rh atoms occupy nearly ideal lattices.
Challenges and opportunities in the bottom-up mechanochemical synthesis of noble metal nanoparticles
(2020)
Mechanochemistry is a promising alternative to solution-based protocols across the chemical sciences, enabling different types of chemistries in solvent-free and environmentally benign conditions. The use of mechanical energy to promote physical and chemical transformations has reached a high level of refinement, allowing for the design of sophisticated molecules and nanostructured materials. Among them, the synthesis of noble metal nanoparticles deserves special attention due to their catalytic applications. In this review, we discuss the recent progress on the development of mechanochemical strategies for the controlled synthesis of noble metal nanostructures. We start by covering the fundamentals of different preparation routes, namely top-down and bottom-up approaches. Next, we focus on the key examples of the mechanochemical synthesis of non-supported and supported metal nanoparticles as well as hybrid nanomaterials containing noble metals. In these examples, in addition to the principles and synthesis mechanisms, their performances in catalysis are discussed. Finally, a perspective of the field is given, where we discuss the opportunities for future work and the challenges of mechanochemical synthesis to produce well-defined noble metal nanoparticles.
Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3.
A new concept called “Ring-Opening Polymerization (ROP) combined with simultaneous POlyCondensation” (ROPPOC) is presented and discussed. This synthetic strategy is based on the intermediate formation of chains having two end groups that can react with each other. The ROPPOC syntheses are subdivided into three groups according to the nature of the chain ends: two ionic end groups, one ionic and one covalent chain end and a combination of two reactive covalent end groups may be involved, depending on the catalyst. The usefulness for the preparation of cyclic polymers is discussed with a review of numerous previously published examples. These examples concern to following classes of cyclic polymers: polypeptides, polyamides, polyesters, including polycarbonates, and cyclic polysiloxanes. It is demonstrated, that the results of certain ROPPOC syntheses are in contradiction to the Jacobson-Stockmayer theory. Finally, the usefulness of ROPPOCs for the detection of polydisperse catenanes is discussed.
The possibility of creating patient-specific individual implants makes Additive Manufacturing technologies of special interest for the medical sector. For substitution of bone defects, powder based Additive Manufacturing by Binder Jetting is a suitable method to produce complex scaffold-like structures made of bioceramics with easily adapted geometries and controlled porosity. The process inherent residual porosity in the printed part, even though desired as it supports bone ingrowth, also leads to limited mechanical strength. Currently, bioceramic scaffolds made by Binder Jetting feature suitable biocompatible and biodegradable properties, while a sufficient mechanical stability is rather challenging. The purpose of this work is to apply the gas flow assisted powder deposition introduced in 2014 by Zocca et al., to the powder bed during printing of bioceramic tablets and scaffolds using α-TCP powder as feedstock. This enables exploiting the advantages of an increased powder bed density, thereby improving the mechanical properties of the printed parts.
In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation.
Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction.
Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time.
This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies.
The study of van der Waals interactions plays a central role in the understanding of bonding across a range of biological, chemical and physical phenomena. The presence of van der Waals interactions can be identified through analysis of the reduced density gradient, a fundamental parameter at the core of Density Functional Theory. An extension of Bader’s Quantum Theory of Atoms in Molecules is developed here through combination with the analysis of the reduced density gradient. Through this development, a new quantum chemical topological tool is presented: the volumetric source function.
This technique allows insight into the atomic composition of van der Waals interactions, offering the first route towards applying the highly successful source function to these disperse interactions. A new algorithm has been implemented in the open-source code, CRITIC2, and tested on acetone, adipic and maleic acids molecular crystals, each stabilized by van der Waals interactions. This novel technique for studying van der Waals interactions at an atomic level offers unprecedented opportunities in the fundamental study of intermolecular interactions and molecular design for crystal engineering, drug design and bio-macromolecular processes.
The characteristics of TiO2 coatings can greatly influence their final performance in large‐scale applications. In the present study, self‐assembly of TiO2 nanoparticles (NPs) in multiple layers was selected as a deposition procedure on various substrates. For this, the main prerequisite constitutes the surface modification of both NPs and substrate with, for example, silane coupling agents. A set of functionalized TiO2 NPs has been produced by reaction with either (3‐aminopropyl)triethoxysilane (APTES) or (3‐aminopropyl)phosphonic acid (APPA) to functionalize the NP surface with free amino‐groups. Then, the complementary functionalized NP set can be obtained from an aliquot of the first one, through the conversion of free surface amino groups to aldehydes by reaction with glutaraldehyde (GA). Several types of TiO2 NPs differing in size, shape, and specific surface area have been functionalized. Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), SEM/ energy‐dispersive X‐ray spectroscopy (EDS), XPS, Auger electron spectroscopy (AES), and Time‐of‐Flight (ToF)‐SIMS analyses have been carried out to evaluate the degree of functionalization, all the analytical methods employed demonstrating successful functionalization of TiO2 NP surface with APTES or APPA and GA.
The very strong Lewis acid aluminium chlorofluo-ride (ACF) was loaded with anhydrous HF. The interactionbetween the surface of the catalyst and HF was investigatedusing a variety of characterization methods, which revealed he formation of polyfluorides. Moreover, the reactivity ofthe HF-loaded ACF towards the hydrofluorination of alkyneswas studied.
The adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon. Varying amounts of carbamazepine were adsorbed onto three different activated carbons, which were subsequently dried, and their thermal decomposition mechanisms examined. The discovery of 55 different pyrolysis products allowed differentiations to be made between specific adsorption sites and conditions. However, the same adsorption mechanisms were found for all samples, which were enhanced by inorganic constituents and oxygen containing surface groups. Furthermore, increasing the loadings led to the evolution of more hydrated decomposition products, whilst parts of the carbamazepine molecules were also integrated into the carbon structure. It was also found that the chemical composition, especially the degree of dehydration of the activated carbon, plays an important role in the adsorption of carbamazepine. Hence, it is thought that the adsorption sites may have a higher adsorption energy for specific adsorbates, when the activated carbon can then potentially increase its degree of graphitisation.
Background: The ubiquitous occurrence of microplastic particles in marine and aquatic ecosystems was intensively investigated in the past decade. However, we know less about the presence, fate, and input paths of microplastic in terrestrial ecosystems. A possible entry path for microplastic into terrestrial ecosystems is the agricultural application of sewage sludge and solid bio-waste as fertilizers. Microplastic contained in sewage sludge also includes Polyethylene terephthalate (PET), which could originate as fiber from textile products or as a fragment from packaging products (foils, bottles, etc.). Information about microplastic content in such environmental samples is limited yet, as most of the used analytical methods are very time-consuming, regarding sample preparation and detection, require sophisticated analytical tools and eventually need high user knowledge.
Results: Here, we present a simple, specific tool for the analysis of PET microplastic particles based on alkaline extraction of PET from the environmental matrix and subsequent determination of the monomers, terephthalic acid, using liquid chromatography with UV detection (LC-UV). The applicability of the method is shown for different types of PET in several soil-related, terrestrial environmental samples, e.g., soil, sediment, compost, fermentation residues, but also sewage sludge, suspended particles from urban water management systems, and indoor dust. Recoveries for model samples are between 94.5 and 107.1%. Limit of determination and limit of quantification are absolute masses of 0.031 and 0.121 mg PET, respectively. In order to verify the measured mass contents of the environmental samples, a method comparison with thermal extraction-desorption-gas chromatography–mass spectrometry (TED-GC/MS) was conducted. Both methods deliver similar results and corroborated each other. PET mass contents in environmental samples range from values below LOQ in agriculture soil up to 57,000 mg kg−1 in dust samples.
Conclusions: We demonstrate the potential of an integral method based on chemical extraction for the Determination of PET mass contents in solid environmental samples. The method was successfully applied to various matrices and may serve as an analytical tool for further investigations of PET-based microplastic in terrestrial ecosystems.
In the present study, hexamethylene diisocyanate (HMDI) encapsulated poly-thiourea formaldehyde (PTF) (10 wt%) coating was developed in an epoxy-polyamine matrix and their anticorrosion studies on Type SS304 stainless steel substrate have been conducted using electrochemistry techniques. The compact and hydrophobic shell wall of PTF proved to be a potent shell wall material for HMDI encapsulation. The effect of temperature and pH values was found to be decisive factor in the synthesis of microcapsules. The PTF microcapsules were synthesized in acidic condition with a pH value of 3. Over 90% of the core fraction is retained in water after 21 days immersion. However, core content decreased with increasing temperature. The capsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Electrochemical Impedance spectroscopy (EIS). Scanning electron microscopic analysis depicts the uniform morphology of coating with a particle size in the range of 1.08 µm–22.06 µm.
The vibrational band at 2271 cm−1 attributed to NCO signal further endorses the successful encapsulation of HMDI into the PTF capsules. Electrochemical testing on steel specifies the appreciable anticorrosion performance of the synthesized poly thiourea formaldehyde (PTF) coating against artificial sea water.
Numerous new tin catalysts that enable the synthesis of cyclic polylactides with broad variation in their molecular mass were recently developed. The abundance of cyclics in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra is, however, frequently reported to greatly exceed that of linears. Thus, the MALDI ionization behavior of various end-capped linear poly(L-lactide)s and one cyclic poly(L-lactide) was investigated and compared.
Neat compounds and various blends of cyclic and linear species were prepared and studied under identical conditions with regard to sample preparation and instrumental condition, except for the laser power. For this purpose, two different MALDI-TOF mass spectrometers were applied.
Our results reveal that cyclics indeed show a slightly better ionization in MALDI, although their ionization as a neat compound seems to be less effective than that of linear polylactides. The ionization of most linear polylactides investigated does not depend on the end group structure. However, linear polylactides containing 12-bromododecyl end groups reveal an unexpected saturation effect that is not caused by fragmentation of the polymer or the end group, or by electronic saturation of the detector digitizer. Furthermore, polylactides with a 2-bromoethyl end group did not show such a saturation effect.
An overestimation of cyclic species in MALDI-TOF mass spectra of poly(L-lactide)s must be considered, but the commonly assumed peak suppression of linear polymers in mixtures of both structures can be excluded.
Cyclic poly(L-lactide)s were prepared by ring-opening polymerization combined with simultaneous polycondensation (ROPPOC) in bulk at 160 ° with dibutyltin bis(4-cyanophenoxide) as catalyst. It is demonstrated by MALDI TOF mass spectrometry and 1H NMR end group analyses that cycles are formed by endto-end cyclization in addition to “back-biting” transesterification. Formation of high molar mass cyclic poly L-lactide)s by means of several more reactive ROPPOC catalysts presented previously and in new experiments is discussed. These experimental results, together with theoretical arguments, prove that part of the Jacobson–Stockmayer theory is wrong. The critical monomer concentration, above which end-toend cyclization is seemingly impossible, does not exist and reversible like irreversible polycondensations can theoretically proceed up to 100% conversion, so that finally all reaction products will necessarily adopt a cyclic architecture.
Ring–Ring Equilibration in Solid, Even-Numbered Cyclic Poly(l-lactide)s and their Stereocomplexes
(2020)
Even-numbered cyclic poly(d-lactide) and poly(l-lactide) are prepared by ringexpansion polymerization. The cyclic pol(l-lactide) is annealed either at 120 or at 160 °C for several days. The progress of transesterification in the solid state is monitored by the formation of odd-numbered cycles via matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The changes of the crystallinity are monitored by differential scanning calorimetry, wideand small-angle x-ray scattering (WAXS and SAXS) measurements. Despite total even-odd equilibration at 160 °C, the crystallinity of poly(l-lactide) is not reduced. Furthermore, the crystallinity of the stereocomplexes of both cyclic polylactides do not decrease or vanish, as expected, when a blocky or random stereosequence is formed by transesterification. This conclusion is confirmed by 13C NMR spectroscopy. These measurements demonstrate that transesterification is a ring–ring equilibration involving the loops on the surfaces of the lamellar crystallites thereby improving crystallinity and 3D packing of crystallites without significant broadening of the molecular weight distribution.
Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows under certain conditions methanogenic archaea can cause higher corrosion than SRB, specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and that spatial statistical evaluations of MIC can be carried out.
This paper reports results from in situ electrochemical X-ray absorption near-edge spectroscopy (XANES) studies of the corrosion processes on model thin iron films in the presence of iron reducing bacteria Shewanella putrefaciens. Here we investigate the electrochemical activity of two cultures grown in the presence and absence of Fe(III) citrate in the culture medium. The XANES spectra and the OCP data of the Fe sample incubated with the culture grown in absence of Fe(III) did not show any significant changes during twenty hours of monitoring. In the case of the culture grown in Fe(III) containing medium, an accelerated dissolution of the iron film was observed together with the formation of a mixed Fe(II)-Fe(III) hydroxide surface layer. The open circuit potential (OCP) steadily approached the free corrosion potential of iron in neutral chloride containing electrolytes, indicating a continuous dissolution process without passivation.
We describe and demonstrate a novel experimental approach to measure broadband, amplitude- and phase-resolved scattering spectra of single nanoparticles with 10-nm spatial resolution. Nanofocusing of Surface plasmon polaritons (SPPs) propagating along the shaft of a conical gold taper is used to create a spatially isolated, spectrally broad nanoscale light source at ist very apex. The interference between these incident SPPs and SPPs that are backpropagating from the apex leads to the formation of an inherently phase-stable interferogram, which we detect in the far field by partially scattering SPPs off a small protrusion on the taper shaft. We show that these interferograms allow the reconstruction of both the amplitude and phase of the local optical near fields around individual nanoparticles optically coupled to the taper apex. We extract local light scattering spectra of particles and quantify line broadenings and spectral shifts induced by tip-sample coupling. Our experimental findings are supported by corresponding finite-difference time-domain and coupled dipole simulations and Show that, in the limit of weak tip-sample coupling, the measurements directly probe the projected local density of optical states of the plasmonic system. The combination of a highly stable inline interferometer with the inherent optical background suppression through nanofocusing makes it a promising tool for the locally resolved study of the spectral and temporal optical response of coupled hybrid nanosystems.
The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters.
A new kind of high melting (HTm) pol(L-lactide) was discovered when cyclic poly(L-lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. By DSC measurements with 10 K min−1 melting temperatures (Tm) in the range of 190–196 °C were found. The WAXS and SAXS measurements evidenced that not a new crystal lattice but a well-ordered morphology and a higher perfection of the crystallites are responsible for the high Tm values and high crystallinities. Under identical reaction conditions SnOct2-catalyzed and alcohol-initiated ROPs do not yield these crystallites.
Furthermore, it was found that the standard crystallites are kinetically favored upon rapid crystallization, whereas the high melting form of poly(L-lactide) is thermodynamically more stable.
Nickel nanoparticles are an active research area due to their multiple applications as catalysts in different processes. A variety of preparation techniques have been reported for the synthesis of these nanoparticles, including solvothermal, microwave-assisted, and emulsion techniques. The well-studied solvothermal oleylamine synthesis route comes with the drawback of needing standard air-free techniques and often space-consuming glassware. Here, we present a facile and straightforward synthesis method for size-controlled highly monodisperse nickel nanoparticles avoiding the use of, e.g., Schlenk techniques and space-consuming labware. The nanoparticles produced by this novel synthetic route were investigated using small-angle X-ray scattering, transmission electron microscopy, X-ray diffraction, and X-ray spectroscopy. The nanoparticles were in a size range of 4–16 nm, show high sphericity, no oxidation, and no agglomeration after synthesis.
Tuning and controlling the solid-state photophysical properties of organic luminophore are very important to develop next-generation organic luminescent materials. With the aim of discovering new functional luminescent materials, new cocrystals of 9-anthracene carboxylic acid (ACA) were prepared with two different dipyridine coformers: 1,2-bis(4-pyridyl)ethylene and 1,2-bis(4-pyridyl)ethane. The cocrystals were successfully obtained by both mechanochemical approaches and conventional solvent crystallization. The newly obtained crystalline solids were characterized thoroughly using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. Structural analysis revealed that the cocrystals are isostructural, exhibiting two-fold interpenetrated hydrogen bonded networks. While the O–H···N hydrogen bonds adopts a primary role in the stabilization of the cocrystal phases, the C–H···O hydrogen bonding interactions appear to play a significant role in guiding the three-dimensional assembly. Both π···π and C–H···π interactions assist in stabilizing the interpenetrated structure. The photoluminescence properties of both the starting materials and cocrystals were examined in their solid states. All the cocrystals display tunable photophysical properties as compared to pure ACA. Density functional theory simulations suggest that the modified optical properties result from charge transfers between the ACA and coformer molecules in each case. This study demonstrates the potential of crystal engineering to design solid-state luminescence switching materials through cocrystallization.
In the present work a series of design rules are developed in order to tune the morphology of TiO2 nanoparticles through hydrothermal process. Through a careful experimental design, the influence of relevant process parameters on the synthesis outcome are studied, reaching to the develop predictive models by using Machine Learning methods. The models, after the validation and training, are able to predict with high accuracy the synthesis outcome in terms of nanoparticle size, polydispersity and aspect ratio. Furthermore, they are implemented by reverse engineering approach to do the inverse process, i.e. obtain the optimal synthesis parameters given a specific product characteristic. For the first time, it is presented a synthesis method that allows continuous and precise control of NPs morphology with the possibility to tune the aspect ratio over a large range from 1.4 (perfect truncated bipyramids) to 6 (elongated nanoparticles) and the length from 20 to 140 nm.
The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde.
This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1
Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack.
In a recent publication the authors have presented theoretical and experimental results indicating that the Jacobson–Stockmayer (JS) theory does not provide a correct description of reversible polycondensations for all polymers and for high conversions (e.g. polycondensation in bulk). In this context reversibility means that all condensation step whether resulting in chain growth or in cyclization are reversible and thus, part of an equilibrium. The first two sections of that paper were focused on the demonstration that small, and above all, large cycles can be formed by end-to-end (ete) cyclization in reversible like in irreversible polycondensations. A significant contribution of ete-cyclization to the course of reversible polycondensations was denied by J + S apparently as a contribution to Florýs dogma, that the end groups of long polymer chains will never meet.
The effect of the presence of Fe(III) during the cultivation on the electrochemical activity and corrosion behaviour of dissimilatory iron reducing bacteria Shewanella putrefaciens was studied by means of ex situ and in situ X-ray absorption near-edge spectroscopy (XANES). Stainless steel AISI 304 and thin iron films were studied as substrates. XANES analysis indicated an accelerated iron dissolution and growth of an oxide/hydroxide film for the culture grown with Fe(III) in comparison to the culture grown in absence of Fe(III). Electrochemical Analysis indicated that the biofilm resulted in acceleration of the general corrosion but provides protection against local corrosion.
The catalytic potential of bismuth subsalicylate (BiSub), a commercial drug, for ring-opening polymerization (ROP) of L-lactide was explored by variation of co-catalyst and polymerization time. Various monofunctional phenols or carboxylic acids, aromatic ortho-hydroxy acids and diphenols were examined as potential co-catalysts. 2,2´-Dihydroxybiphenyl proved to be the most successful co-catalyst yielding weight average molecular weights (uncorrected Mw values up to 185 000) after optimization of reaction time and temperature. Prolonged heating (>1-2h) depending on catalyst concentration) caused thermal degradation. In polymerization experiments with various commercial Bi(III) salts a better alternative to BiSub was not found. By means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry a couple of unusual and unexpected transesterification reactions were discovered. Finally, the effectiveness of several antioxidants and potential catalyst poisons was explored, and triphenylphosphine was found to be an effective catalyst poison.
As the most electronegative element, fluorine has a strong influence on material properties such as absorption behaviour or chemical and thermal stability. Fluorine can be easily integrated into coordination polymers (CPs) via a fluorinated acetate, here trifluoroacetate in Ba(CF3COO)2, or directly via a metal fluorine bond (BaF(CH3COO)). In the present study both possibilities of fluorine integration were tested and their effect on structure and properties of barium coordination polymers was investigated in comparison with the non-fluorinated barium acetate (Ba(CH3COO)2). In addition to the study of their thermal behaviour and their decomposition temperature, the CPs structures were tested for their application as possible anode materials in lithium ion batteries and for their sorption of water and ammonia. The properties of the CPs can be traced back to the individual structural motifs and could thus trigger new design ideas for CPs in LIBs and/or catalysis.
The synthesis and optimization of superior and eco-friendly sorbents for Pb(II) pose a great challenge in the field of water treatment. The sorbent was developed by introducing graphene oxide (GO) into the matrix of polyvinyl formaldehyde (PVF) foam. The immobilization of GO in PVF results in significant increase in the maximum adsorption capacity (Qt) of GO powder for Pb(II), from ≈800 to ≈1730 mg g−1 in the case of GO/PVF foam. As compared with GO powder in Pb(II) aqueous solutions, PVF matrix keeps GO sheets stable without any agglomeration. The large surface area of GO sheet allows the abundant oxygenated functional groups on its surface to participate effectively in the Pb(II) adsorption process, leading to the huge increase of the Qt. Adsorption isotherms and kinetic studies indicated that the sorption process of Pb(II) on GO/PVF was done on heterogenous surface by ion-exchange reaction. The GO/PVF foam showed an excellent reusability for more than 10 cycles with almost the same efficiency and without any significant change in its physical properties.
The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process.
By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)‐stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5±1 nm and an edge length of about 175±17 nm, the AOT bilayer is replaced by a polymeric HA‐layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA‐shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon‐driven dimerization of 4‐nitrothiophenol (4‐NTP) to 4,4′‐dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing.
This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization.