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Post-mechanical plating heat treatment induces the formation of an iron–zinc (Fe-Zn) rich intermetallic layer between Zn and ZnSn coatings and the substrate. Despite increased outer coating porosity, the corrosion resistance of Zn- and ZnSn-coated steels significantly improves after heat treatment, attributed to the formation of intermetallic phases. This study employs small- and ultra-small-angle neutron scattering (SANS and USANS) to investigate the behavior of mechanically plated Zn and ZnSn coatings pre- and post-heat treatment. In the presence of a relatively thick steel substrate, strong multiple scattering occurs. However, by identifying a specific high Q-range region where multiple scattering is negligible, we reveal small but significant differences. Porod's slopes, denoted as 'n', are calculated for uncoated steel, and Zn- and ZnSn-coated steels (both with and without heat treatment). These slope values reflect contributions from different interfaces on the particles' surface roughness. Despite the challenges of multiple scattering, our findings offer valuable insights into coatings' behavior. The study lays a foundation for future investigations into coating behavior using SANS/USANS techniques. [ABSTRACT FROM AUTHOR]

Bioplastic films comprising both plant- and animal-derived proteins have the potential to integrate the optimal characteristics inherent to the specific domain, which offers enormous potential to develop polymer alternatives to petroleum-based plastic. Herein, we present a facile strategy to develop hybrid films comprised of both wheat gluten and wool keratin proteins for the first time, employing a ruthenium-based photocrosslinking strategy. This approach addresses the demand for sustainable materials, reducing the environmental impact by using proteins from renewable and biodegradable sources. Gluten film was fabricated from an alcohol–water mixture soluble fraction, largely comprised of gliadin proteins. Co-crosslinking hydrolyzed low-molecular-weight keratin with gluten enhanced its hydrophilic properties and enabled the tuning of its physicochemical properties. Furthermore, the hierarchical structure of the fabricated films was studied using neutron scattering techniques, which revealed the presence of both hydrophobic and hydrophilic nanodomains, gliadin nanoclusters, and interconnected micropores in the matrix. The films exhibited a largely (>40%) β-sheet secondary structure, with diminishing gliadin aggregate intensity and increasing micropore size (from 1.2 to 2.2 µm) with an increase in keratin content. The hybrid films displayed improved molecular chain mobility, as evidenced by the decrease in the glass-transition temperature from ~179.7 °C to ~173.5 °C. Amongst the fabricated films, the G14K6 hybrid sample showed superior water uptake (6.80% after 30 days) compared to the pristine G20 sample (1.04%). The suitability of the developed system for multilayer 3D printing has also been demonstrated, with the 10-layer 3D-printed film exhibiting >92% accuracy, which has the potential for use in packaging, agricultural, and biomedical applications. [ABSTRACT FROM AUTHOR]

The microstructure of minerals and rocks can significantly alter reaction rates. This study focuses on identifying transport paths in low porosity rocks based on the hypothesis that grain boundary widening accelerates reactions in which one mineral is replaced by another (replacement reaction). We conducted a time series of replacement experiments of three limestones (CaCO3) of different microstructures and solid impurity contents using FeCl2. Reacted solids were analyzed using chemical imaging, small angle X-ray and neutron scattering and Raman spectroscopy. In high porosity limestones replacement is reaction controlled and complete replacement was observed within 2 days. In low porosity limestones that contain 1–2% dolomite impurities and are dominated by grain boundaries, a reaction rim was observed whose width did not change with reaction time. Siderite (FeCO3) nucleation was observed in all parts of the rock cores indicating the percolation of the solution throughout the complete core. Dolomite impurities were identified to act as nucleation sites leading to growth of crystals that exert force on the CaCO3 grains. Widening of grain boundaries beyond what is expected based on dissolution and thermal grain expansion was observed in the low porosity marble containing dolomite impurities. This leads to a self-perpetuating cycle of grain boundary widening and reaction acceleration instead of reaction front propagation. [ABSTRACT FROM AUTHOR]

Ultra‐small‐angle neutron scattering (USANS) and small‐angle neutron scattering (SANS) measurements, covering length scales from micrometres to nanometres, were made to investigate the structure of nanodiamonds (NDs) and their suspensions. These nanodiamonds were produced by two different techniques, namely by the detonation method and by the laser ablation of a carbon–hydrocarbon mixture. The (U)SANS results indicated the presence of structures four orders of magnitude larger than the dimensions of a single ND particle, consisting of aggregations of ND particles. This aggregation of the ND particles was studied by employing the contrast variation technique. Two different solvents, namely H2O and dimethyl sulfoxide (and their deuterated counterparts), were used to understand the role of hydrogen in the shape and size of the aggregates. The analysis of experimental data from SANS measurements also reveals the ND particles to have an ellipsoidal structure. Using a defined shape model and the SANS contrast variation technique, it was possible to characterize the non‐diamond outer shell of the particles and determine the outer layer thickness. This clarification of the structure of the NDs will allow better preparation of suspensions/samples for various applications. Understanding the structure of NDs at multiple length scales also provides crucial knowledge of particle–particle interaction and its effect on the aggregation structures. [ABSTRACT FROM AUTHOR]

In this work, a polymer and ionic liquid (IL) hybrid with superior thermoelectric performance is prepared via a system design of the chemical composition, molar ratio of the constituent molecules and manipulating the structure in solution and dried films. The solution-casted hybrid film, consisting of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and 1-ethyl-3-methylimidazolium tricyanomethanide (EMIM:TCM), shows the highest power factor of 175 μW m−1 K−2 in the polymer hybrid prepared by a post-treatment-free method. With a set of complementary structure characterization methods, it is found that EMIM:TCM can induce the structure reorganization of PEDOT:PSS in solution from a core-shell model to a rod-like model, during which PEDOT partially separates from PSS that eases the conductive network formation. In addition, the oxidation level of PEDOT:PSS is reduced by adding EMIM:TCM. Based on which, the PEDOT:PSS/IL hybrid shows the best performance in optimizing the conductivity (1163 S cm−1) and Seebeck coefficient (38.8 μV K−1) simultaneously. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first study to monitor gastric devolution of casein gels using USANS and SANS. • Gels prepared in D 2 O exhibit earlier onset of gelation, are firmer yet more brittle compared to H 2 O. • Rennet-induced gel structure is sensitive to the acidic environment of the stomach. • Pepsin induces micelle swelling and promotes higher levels of protein digestion in the stomach. • Acidification and shear govern early gastric digestion kinetics. This study aimed to understand the structural devolution of 10% w/w rennet-induced (RG) and transglutaminase-induced acid (TG) gels in H 2 O and D 2 O under in vitro gastric conditions with and without pepsin. The real-time devolution of structure at a nano- (e.g. colloidal calcium phosphate (CCP) and micelle) and micro- (gel network) level was determined using ultra-small (USANS) and small-angle neutron scattering (SANS) with electron microscopy. Results demonstrate that gel firmness or elasticity determines disintegration behaviour during simulated mastication and consequently the particle size entering the stomach. Shear of mixing in the stomach, pH, and enzyme activity will also affect the digestion process. Our results suggest that shear of mixing primarily results in erosion at the particle surface and governs gel disintegration behaviour during the early stages of digestion. Pepsin diffusivity, and hence action, occur more readily in the latter stages of gastric digestion via access to the particle interior. This occurs via the progressively larger pores of the looser gel network and channels created within the larger, less dense casein micelles of the RG gels. Gel firmness and brittleness were greater in the D 2 O samples compared to H 2 O, facilitating gel disintegration. Despite the higher strength and elasticity of RG compared to TG, the protein network strands of the RG gels become more compact when exposed to the acidic gastric environment with comparatively larger pores observed through SEM imaging. This led to a higher degree of digestibility in RG gels compared to TG gels. This is the first study to examine casein gel structure during simulated gastric digestion using scattering and highlights the benefits of neutron scattering to monitor structural changes during digestion at multiple length scales. [ABSTRACT FROM AUTHOR]

A major challenge in understanding nanoplastic toxicity (or nanoparticles in general) lies in establishing the causal relationships between its physical properties and biological impact. This difficulty can be attributed to surface alterations that follow the formation of a biological complex around the nanoplastic, as exemplified by protein coronae. The protein corona is known to be responsible for the biological response elicited, although its own structure and attributes remain unknown. We approach this knowledge gap by independently studying the structure of soft and hard coronae using neutron scattering techniques. We investigated the formation and the structure of corona proteins (human serum albumin and lysozyme) and the resulting protein corona complexes with polystyrene nanoplastics of different sizes (20 and 200 nm) and charges. Soft corona complexes (regardless of protein type) adopted a structure where the nanoplastics were surrounded by a loose protein layer (∼2–3 protein molecules thick). Hard corona complexes formed fractal-like aggregates, and the morphology of which is known to be harmful to cellular membranes. In most cases, hard-corona coated nanoplastics also formed fractal-like aggregates in solution. Nanoplastic size affected the structures of both the protein corona and the intrinsic protein: more significant conformational change was observed in the hard corona proteins around smaller nanoparticles compared to larger ones, as the self-association forces holding the nanoplastic/protein complex together were stronger. This also implies that protein-dependent biochemical processes are more likely to be disrupted by smaller polystyrene nanoplastics, rather than larger ones. [ABSTRACT FROM AUTHOR]

QUOKKA is a 40 m pinhole small‐angle neutron scattering instrument in routine user operation at the OPAL research reactor at the Australian Nuclear Science and Technology Organisation. Operating with a neutron velocity selector enabling variable wavelength, QUOKKA has an adjustable collimation system providing source–sample distances of up to 20 m. Following the large‐area sample position, a two‐dimensional 1 m2 position‐sensitive detector measures neutrons scattered from the sample over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument to conduct research across a broad range of scientific disciplines, from structural biology to magnetism. As it has recently generated its first 100 publications through serving the needs of the domestic and international user communities, it is timely to detail a description of its as‐built design, performance and operation as well as its scientific highlights. Scientific examples presented here reflect the Australian context, as do the industrial applications, many combined with innovative and unique sample environments. [ABSTRACT FROM AUTHOR]

In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-resilin. The structural transition of Rec1-resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-resilin in response to the changes in concentration, pH, and temperature. Rec1-resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ~ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduces with a progressive increase in concentration, and molecular chains transform from a Gaussian coil to a fully swollen coil. It is also revealed that the structural organization of Rec1-resilin dynamically transforms from a rod (pH 2) to coil (pH 4.8) and to globular (pH 12) as a function of pH. The findings further support the temperature-triggered dual-phase-transition behavior of Rec1-resilin, exhibiting rod-shaped structural organization below the upper critical solution temperature (~4 °C) and a large but compact structure above the lower critical solution temperature (~75 °C). This work attempted to correlate unusual responsiveness of Rec1-resilin to the evolution of conformational ensembles. [ABSTRACT FROM AUTHOR]

Abstract: Inverse micelles play an important role in the stability of high internal phase water in oil (W/O) emulsions. The influence of both solvent and temperature has been investigated on the structure of inverse micelles prepared from the polyisobutylene-based surfactant, PIBSA, using small-angle neutron scattering (SANS). By collecting data over an extended range of scattering vector (Q), combined with the use of solvent deuteration, SANS has highlighted an additional contribution to the anticipated micellar scattering, namely a signal characteristic of rod-like scattering that is consistent with single dissolved molecules of the PIBSA surfactant and its primarily hydrogenated (mainly alkane oil) solvent (both MW ca. 1000Da). The solvency effect of three different solvents (hexadecane, cyclohexane and toluene) on micellar–monomer (rod) equilibrium has also been evaluated. The volume fractions of rods and micelles in solution are found to agree with the sample compositions, as does the intensity of the observed incoherent background. This consistency across fit parameters not only highlights the sensitivity of the model but also the value of extended Q range, enhanced signal-to-noise studies in such soft matter systems. The data show the extent to which quantitative measurements can be carried at the molecular level using small angle scattering. [Copyright &y& Elsevier]

Porosity is a key parameter on thermal barrier coatings, directly influencing thermal conductivity and strain tolerance. Suspension high velocity oxy-fuel (SHVOF) thermal spraying enables the use of sub-micron particles, increasing control over porosity and introducing nano-sized pores. Neutron scattering is capable of studying porosity with radii between 1 nm and 10 μm, thanks to the combination of small-angle and ultra-small-angle neutron scattering. Image analysis allows for the study of porosity with radii above ∼100 nm. For the first time in SHVOF 8YSZ, pore size distribution, total porosity and pore morphology were studied to determine the effects of heat treatment. X-ray diffraction and micro-hardness measurements were performed to study the phase transformation, and its effects on the mechanical properties. The results show an abundant presence of nano-pores in the as-sprayed coatings, which are eliminated after heat treatment at 1100 °C; a transition from inter-splat lamellar to globular pores and the appearance of micro-cracks along with the accumulation of micro-strains associated with the phase transformation at 1200 °C. [ABSTRACT FROM AUTHOR]

Small angle neutron scattering (SANS) responses of particulate silica as disordered and ordered porous and non-porous powders were obtained. Each classification provided distinct scattering patterns which were fitted and analysed using Guinier-Porod and mass-surface fractal (msf) models. The resulting particle dimensions showed good agreement with the same from nitrogen gas adsorption analyses. Additionally, the excellent fit of the msf model to the non-porous silica scattering response resulted in an agreement between the mass and surface fractal dimension values for it and similar analyses and results published previously for fumed silica. The msf fitting gave additional insight into particle and cluster scattering dimensions with particle dimensions being consistent with those from the G-P analyses. [ABSTRACT FROM AUTHOR]

The microstructure of minerals and rocks can significantly alter reaction rates. This study focuses on identifying transport paths in low porosity rocks based on the hypothesis that grain boundary widening accelerates reactions in which one mineral is replaced by another (replacement reaction). We conducted a time series of replacement experiments of three limestones (CaCO3) of different microstructures and solid impurity contents using FeCl2. Reacted solids were analyzed using chemical imaging, small angle X-ray and neutron scattering and Raman spectroscopy. In high porosity limestones replacement is reaction controlled and complete replacement was observed within 2 days. In low porosity limestones that contain 1–2% dolomite impurities and are dominated by grain boundaries, a reaction rim was observed whose width did not change with reaction time. Siderite (FeCO3) nucleation was observed in all parts of the rock cores indicating the percolation of the solution throughout the complete core. Dolomite impurities were identified to act as nucleation sites leading to growth of crystals that exert force on the CaCO3 grains. Widening of grain boundaries beyond what is expected based on dissolution and thermal grain expansion was observed in the low porosity marble containing dolomite impurities. This leads to a self-perpetuating cycle of grain boundary widening and reaction acceleration instead of reaction front propagation. [ABSTRACT FROM AUTHOR]

Nanoparticles are vital to a broad range of applications including commercial formulations, sensing and advanced material synthesis. Nanoparticles can come in a variety of shapes including cubes, polyhedra, rods, and prisms, and recent literature has demonstrated the importance of nanoparticle shape to downstream function (such as cellular uptake). While researchers routinely characterise nanoparticle shape using electron microscopy techniques, this generally requires drying of the samples. Many particles (e.g. lipid nanoparticles or polymer particles) change with drying, so complementary solution based techniques are needed. Scattering techniques can be used to characterise such nanoparticles in suspension, overcoming many of the limitations of other techniques. Here we review the current state of the art in the characterisation of complex nanoparticles (non-spherical and multi-layered) using advanced scattering techniques including light, X-ray, and neutron scattering. Recent improvements in instrument availability and data analysis makes these techniques much more accessible to researchers. This review provides an introduction to these techniques aimed at all researchers working with nanoparticles, in the hope that full characterisation of nanoparticles in solution becomes standard practice. [Display omitted] • Scattering techniques can be used to characterise complex nanoparticles in solution. • Light, X-ray, and neutron scattering probe different length scales and can examine different aspects of a particular system. • Advances in scattering techniques and analysis allows detailed characterisation of non-spherical and multi-component systems. [ABSTRACT FROM AUTHOR]

The structure–property studies in unpolymerized and polymerized tannic acid incorporated hydrogels exhibited the presence of micron sized aggregates. The hydrogen bonded aggregates breaks at high temperatures for the unpolymerized and polymerized cases as evident from the scattering studies. The structural changes is clearly reflected in rheological properties for the unpolymerized case as a clear elastic to dissipative transition while the polymerized case exhibited dissipation even at higher temperatures. [Display omitted] Hydrogels made with semi-interpenetrating networks of the oligomerized polyphenol tannic acid, and poly(acrylamide), exhibit high stiffness and toughness. However, the structure property relationships that give rise to enhanced mechanical properties is not well understood. Herein, we systematically investigate the hydrogels using small angle X-ray scattering and small and Ultra-small angle neutron scattering within a wide length scale range (1 nm to 20 µm), polarized optical microscopy, and rheology. Small angle X-ray and neutron scattering reveal the presence of micron sized hydrogen bonded clusters in the hydrogels. Breaking of hydrogen bonded clusters above a critical solution temperature was clearly observed in the small angle neutron scattering data. Polarized optical microscopy show enhanced anisotropy for the gels with oligomerized tannic acid incorporated - when compared to gels with monomeric tannic acid. Rheological studies at varying temperatures nicely corroborate the structural changes observed at high temperatures and reveal a self-healing behavior of the gels. The knowledge gained from this study will aid in rational design of hydrogels for biomedical applications. [ABSTRACT FROM AUTHOR]

Abstract: The changes in structure of high internal phase emulsions at low concentrations and at elevated temperature are reported for comparison with the same emulsions under conditions well away from instability. Small angle neutron scattering measurements on aqueous ammonium nitrate droplets dispersed in hexadecane and stabilized by very small quantities of a polyisobutylene-based surfactant (PIBSA) as well as related inverse micellar solutions in hexadecane, have been made as a function of temperature and surfactant concentration. Experimental conditions here favour larger and more deformable droplets than in previous studies. Besides the expected micelles and adsorbed surfactant, planar bilayers of micron lateral extent between touching droplets cover 20% of the droplet surface. Another difference from previous experiments is that the oil phase in the emulsions, and corresponding inverse micellar solutions are different in micellar radii and composition. The differences, and changes with surfactant concentration and temperature, are attributed to fractionation of the polydisperse PIBSA in the emulsions, but not the inverse micellar solutions. At low PIBSA concentration and high temperature the SANS shows emulsion decomposing into separate oil and aqueous phases. This occurs when the micelle concentration reaches a very small but measurable value. The inverse micelles may suppress by steric action long wavelength unstable capillary waves in the bilayers. Depletion repulsion forces here have a minor role in the emulsion stabilization. [Copyright &y& Elsevier]

The upper Ordovician Wufeng Shale and lower Silurian Longmaxi Shale are part of the Fuling shale gas play located in the south-eastern part of the Sichuan Basin, southern China, representing the first commercial shale gas production project outside North America. We studied the occurrence of porosity at the micro- and nano-scale in samples of contrasting organic richness representing the typical lithofacies from the post-mature part of the Wufeng-Longmaxi gas play. Using a combination of site specific, high-resolution scanning and transmission electron microscopy with bulk measurements based on small angle neutron scattering and cryogenic Argon physisorption, along with conventional organic petrology, we highlight the impact of different types of organic matter (OM) (primary versus secondary) on the development of OM-hosted porosity. The results indicate that at the bulk scale the overall porosity in the samples is proportional to their organic content and organic hosted pore account for 30–40% of the total pore volume of the rocks. Nevertheless, most of the pores identified via electron microscopy imaging seem to reside in the organic matter, indicating that potentially a large part of the pores volume detected by neutron scattering and Argon physisorption is visually not detected. Organic matter focused nanoscale imaging revealed that mesopores are preferentially present in the solid bitumen and not in the primary detrital organic particles. Organic lean samples show low porosity and dominance of micropores, while organic-rich samples show higher porosity and a broader spectrum of pore sizes. Importantly, most of the meso pores are located in organic matter petrographically interpreted as solid bitumen, while detrital organic particles like graptolites show minimal visible porosity under high resolution electron microscopy and pore sizes in the micro pore range (i.e. <2 nm). Distinguishing between primary and secondary OM is therefore important for understanding the creation of an interconnected network of porous OM during hydrocarbon migration. This may have an important control on the estimation of gas in place and the gas transport properties of the shale. [Display omitted] [ABSTRACT FROM AUTHOR]