This study investigates the microstructure–property relationships of additively manufactured PLA composites reinforced predominantly with calcium carbonate (CaCO3) mineral fillers. A combined experimental and numerical approach is employed, integrating tensile testing, X-ray micro-tomography, and finite element computation based on reconstructed microstructures. The results show that printing angle strongly affects mechanical performance through its influence on porosity, filament architecture, and interfacial bonding. Mechanical performance improves from 0° to 30°, reaching maximum values of 755 MPa in Young's modulus and 44 MPa in tensile strength. A slight reduction in both stiffness and tensile strength is observed at 45°, indicating that mechanical performance does not increase monotonically with printing angle and that an intermediate angle (30°) provides the most favourable balance between filament architecture and defect distribution. Finite element simulations reveal pronounced stress heterogeneity and confirm the dominant role of microstructural defects in load transfer.The effective mechanical properties are significantly lower than predictions based on the rule of mixtures, indicating inefficient reinforcement and a response approaching the Reuss bound. This behaviour is attributed to limited interfacial load transfer and microstructural defects, demonstrating that interface quality and architecture govern the mechanical response of ceramic-filled PLA systems.

Crystal-chemical features of high-calcium and hypercalcium eudialyte-group minerals (EGMs) from a carbonatite-related rock of the Tamazeght peralkaline complex, High Atlas Mountains, Morocco were studied using electron probe microanalysis, single-crystal X-ray structure analysis, infrared and Raman spectroscopy. The major components of the host rock are calcite, fluorite and EGMs; aegirine-augite is present in subordinate amounts. The specific features of the studied EGMs are chemical heterogeneity, a complex zoning, reaction zones around calcite and apatite inclusions, Na- and Cl-deficiency, high contents of Ca, Mn, REE, Nb, carbonate and H-bearing groups, positive correlation between Nb and Mn and negative correlations between the pairs Fe-Mn and Zr-Mn. These features confirm previous assumptions about the role of infiltration of carbonatite fluid rich in Ca, Mn, REE, Nb, CO2 and H2O and a depletion of Cl in the remaining fluid after the crystallization of sodalite at the expense of nepheline in the formation of carbonatite-related rocks of the Tamazeght complex. The crystal structure of a single-crystal fragment extracted from the Nb-rich zone refined to R-1 = 0.0335 has shown a high degree of ordering of Na, REE and H3O+ and the dominance of Fe3+ at the M2 site with five-fold coordination. The composition of EGMs from the reaction zones around calcite and apatite inclusions corresponds to Mn-dominant (with Mn > Fe at the M2 site) analogue of feklichevite with the simplified formula Ca-3(Na,K)(9)(H3O)(3)Ca6Zr3(Mn2+,Fe3+,Zr)(3)NbSi(Si24O72)(OH,H2O)(5)(F,Cl)(2/3)(CO3)(1/3).

In this study, we explore how the addition of flax fibre residues affects the microstructure and mechanical properties of modified mortars. Flax fibre residues from the individualization process are considered as fillers. Various formulations of mortar are adjusted by incorporating different proportions and sizes of flax fibre residues. The workability of fresh modified mortars is assessed through flow table experiments. X-ray mu -tomography is employed to investigate microstructural changes, focusing on pore content and the 3D spatial arrangement and content of natural residues. Mechanical performance is evaluated through compression tests conducted at different curing times. The findings indicate that flax residues can serve as effective substitutes, resulting in moderate loss in mechanical strength if the particle size is kept below 3 mm. Optimal formulations are found to require sieving of residues particle sizes resulting in small particles of 1 mm for an overall weight content of 5 % in the total weight of the cement used in the mix. These results demonstrate superior mechanical performance compared to all other tested conditions within only 7 curing days.

This study investigates the development of biodegradable, scented bio-composite filaments incorporating industrial residues, specifically spent coffee grounds (SCG) and lignin (LI), into a PLA matrix for FDM 3D printing. Two fragrance additives, essential oil (EO) and microencapsulated fragrance powder (FP), were introduced (3%) to enhance sensory properties. The research investigates the effects of filler content (5%, 10%, and 15%) and fragrance additives on the surface chemistry (FTIR), thermal stability (TGA and DSC), mechanical properties (Tensile, flexural and impact), microstructure, and dimensional stability (Water absorption test and thickness swelling). Incorporating industrial residues and additives into PLA reduced the thermal stability, the degradation temperature and the glass transition temperature but increased the residual mass and the crystallinity. The effect of lignin was more pronounced than that of SCG, significantly influencing these thermal properties. Increasing the filler content of spent coffee grounds and lignin also led to a progressive decrease in tensile, flexural, and impact strength due to poor interfacial adhesion and increased void formation. However, lignin-based biocomposites exhibited enhanced stiffness at lower concentrations (≤10%), while biocomposites containing 15% SCG doubled their elongation at break compared to pure PLA. Adding fragrance reduced the mechanical strength but improved ductility due to plasticizer-like interactions. Microstructural analysis revealed heterogeneity in the biocomposites’ fracture surface characterized by the presence of pores, filler agglomeration, and delamination, indicating uneven filler dispersion and limited interfacial adhesion, particularly at high filler concentrations. The water absorption and dimensional stability of 3D-printed biocomposites increased progressively with the addition of residues. The presence of essential oil slightly improved water resistance by forming hydrogen bonds that limited moisture absorption. This article adds significant value by extending the potential applications of biocomposites beyond conventional engineering uses, making them particularly suitable for the fashion and design sectors, where multi-sensory and sustainable materials are increasingly sought after.

Fifteen opal samples of gem quality from the Spencer Opal Mines in Idaho (USA) were examined. These opals display play-of-colour, with three of them having a pink body colour. The analysis was conducted using standard gemmological tools, along with non-destructive spectroscopic, chemical, and imaging methods. All samples were identified as opal-A, with their play-of-colour resulting from a regular stacking of hydrated silica spheres. However, at times, the spheres are large to allow diffraction. Opal-A are only occasionally found in nature as gems. Inclusion observed in the studied samples included alunite (KAl3(SO4)2(OH)6), anhydrite (CaSO4), and iron-rich spherules (hematite). The pink body colour in the studied specimens is caused by the scattering of light from reddish dendrites. The samples show significant stratification, with fluorescence ranging from green to blue to orange, the latter of which represents a new phenomenon in opals not associated with quinones. Additionally, the orange fluorescence is accompanied by emissions from Sm2+ in anhydrite inclusions.

The bidisperse structure of a natural Brazilian opal was revealed using transmission electron microscopy (TEM). Since TEM enables observation through the transparency of a few layers of silica spheres, the lamellar observation produced a complex image suggesting a flower-like repeating pattern generated by superimposed discs more or less opaque to the electron beam. Analysis of this disc combination revealed that the stacking structure of this opal was a hexagonal Laves phase of MgZn2 type. The cutting plane is parallel to (11 (2) over bar0). A simulation over the thickness of the lamella matched the TEM image very well. The synthesis of such binary colloids is the aim of many experimental and theoretical studies with a variety of industrial applications. This study aims to prove that determining the structure of ordered natural opals can be performed by analysing TEM images.

Meticulous sample preparation and strict adherence to preservation procedures are essential for electron microscopy investigations, which enable accurate capture of organisms’ morphology, size, and potential interactions within the sample. Here, we present a protocol for preserving cells of the model diatom Phaeodactylum tricornutum and its native bacterial community. We describe steps for diatom fixation and coverslip preparation and washing. We then detail procedures for dehydrating, drying, and metallizing samples followed by observation using scanning electron microscopy.

In this study, digital light processing (DLP) was utilized to generate 3D-printed blends composed of photosensitive acrylate-modified polylactic acid (PLA) resin mixed with varying weight ratios of lignin extracted from softwood, typically ranging from 5 wt% to 30 wt%. The microstructure of these 3D-printed blends was examined through X-ray microtomography. Additionally, the tensile mechanical properties of all blends were assessed in relation to the weight ratio and post-curing treatment. The results suggest that post-curing significantly influences the tensile properties of the 3D-printed composites, especially in modulating the brittleness of the prints. Furthermore, an optimal weight ratio was identified to be around 5 wt%, beyond which UV light photopolymerization experiences compromises. These findings regarding acrylate-modified PLA/lignin blends offer a cost-effective alternative for producing 3D-printed bio-sourced components, maintaining technical performance in reasonable-cost, low-temperature 3D printing, and with a low environmental footprint.

Multidimensional, low dose structural and chemical analysis of CDHA mixed with two different hydrogels achieved by cryo-FIB/SEM tomography in combination with cryo-EDS.

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This study aims to relate the microstructural arrangement, in particular the symmetry materialized by filament sequencing in the fused filament fabrication process, to the mechanical behavior of printed polyamide. Dog-bone structures were printed using various printing temperatures ranging from 250 °C to 280 °C, which were combined with part orientation including vertical, horizontal, and lateral configurations and raster angles (0°, 15°, 30°, and 45°) that represent the in-plane and out-of-plane symmetrical arrangement of the filament. Mechanical testing was conducted on both as-received filaments and printed structures to derive the effects of filament arrangement symmetry and process-generated defects on mechanical loss. In addition, a microstructural analysis using scanning electron microscopy was used to share more light on the filament arrangements and their consequence on the deformation mechanisms with respect to the printing conditions. The results showed that the 3D printed polyamide-based materials exhibited remarkable tensile performance with strain stiffening behavior and large elongation at break due to their particular filament layout. Among the considered printing conditions, the part orientation was found to have the largest influence on the tensile behavior, which modulates the behavior from complete restoration of the filament performance to mechanical loss.

Al-doped ZnO thin films with varying Aluminium (Al) content were deposited by radio frequency magnetron cosputtering of two ZnO and Al targets in confocal configuration. A comprehensive study of the effect of Al content variation on the structural, optical and electrical properties were studied for as-deposited films and after an annealing step under controlled argon atmosphere. Chemical composition analyses, performed by both X-ray photoelectron spectroscopy and energy dispersive X-ray spectrometry, show an Al content variation in the deposited films in the 0-14 at.% range by varying the Al target power from 0 to 30 W, while the Zn target power was kept constant at 200 W. All deposited films exhibit a wurtzite crystalline structure and a decreasing crystalline quality for Al content above 5 at.% as shown by grazing incidence X-ray diffraction patterns. Atomic Force Microscopy analysis revealed films with homogeneous and dense surface morphology with roughness in the one nm range. Carrier concentration, resistivity and photoluminescence vary significantly with Al content in the ZnO films and appear optimized for an Al content window ranging from 1.5 to 5.5 at. %. Both optical and electrical properties are improved by a post-annealing at 300 degrees C under argon. A high figure of merit of 43.6 x 10-4 sq.& omega;-1 was obtained for the ZnO film with Al content of 3.6 at.% after annealing at 300 degrees C. Optimized properties are obtained for a higher Al content than the standard value of 2 at. % widely used in published works.

This study addresses the potential of using ceramics-based filaments as a feedstock material in an additive manufacturing process. Tensile specimens of PLA-ceramic (PLC) material are manufactured using a fused deposition modelling process, applying various printing parameters including printing angle and part orientation. Mechanical testing is performed on both the filaments and 3D-printed parts, and the related engineering quantities are derived. The experimental results show that PLC wire properties are substantially restored for the horizontal and lateral printing orientations, with only a 9% reduction in stiffness. In addition, a typical elastic-plastic response is achieved with these orientations, allowing the PLC to achieve excellent stiffness and elongation-at-break performance. The mechanical performance of the PLC is explained by the large proportion of continuous filaments along the loading direction. In addition, the printing angle is found to be a secondary factor allowing for layups at −45°/+45° and 0°/90°, resulting in the best tensile performance. The downside of using PLC is the lack of mechanical transfer, which is associated with weak interfacial behaviour and the inability to achieve high tensile strength.

Using multinuclear copper iodide complexes as cross-linking agents in a polyurethane matrix, original photoluminescent stimuli-responsive materials were synthesized. The intrinsic photoluminescence properties of the covalently incorporated copper iodide complexes are thus transferred to the materials while retaining the beneficial characteristics of the polymer host. The transparent materials exhibit room-temperature phosphorescence with emission switching properties by displaying luminescence thermochromism and solvatochromism. The luminescence thermochromism is characterized by a change in the wavelength and intensity of the emission with temperature, and the vapochromic effect presents a contrasted response of extinction or exaltation according to the nature of the solvent of exposure. By combining the luminescence characteristics of photoactive copper iodide complexes with the ease of polymer processing, the application of these luminescent materials as phosphors in LED (light-emitting diode) devices was also demonstrated. The present study shows that the use of copper iodide complexes as cross-linkers in polymeric materials is a relevant strategy to design materials with enhanced functionalities in addition to their low cost and sustainable characteristics.

The study aims to investigate the origin of the crystalline and compositional bi-layered structure of CuIn1-xGaxS2 (CIGS) films we previously observed for samples deposited following the 3-stage process. Therefore, the growth of films of different gallium contents (i.e. x) was interrupted at key steps of the 3-stage, namely at the end of the first stage, after half of the second stage and at the end of third stage. Compositional, morphological and structural differences at each stage were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-Ray Spectroscopy (EDX). From these investigations, we propose a model attributing composition plateaus to the formation of diverse Cu-poor crystalline phases during the second stage of the growth process.

New anhydrous alkali lanthanide-free polyoxometalates have been elaborated by thermal decomposition of their parent hydrates, and they exhibit remarkable reversible turn-off-on luminescence properties at room temperature in the presence of humidity.

In the present study, MoO3:MoS2 hybrid thin layers have been synthesized through partial oxidation of MoS2. We have demonstrated that the reaction requires darkness conditions to decrease the oxidation rate, thus obtaining the hybrid, MoO3:MoS2. A simple liquid-phase exfoliation (LPE) is carried out to achieve homogenous MoS2 nanoflakes and high reproducibility of the results after MoS2 oxidation. XPS analyses reveal the presence of MoO3, MoS2, and MoOxSy in the hybrid layer. These results are also confirmed by X-ray diffraction and high-resolution TEM. Optical absorbance reveals that the absorption peaks of the MoO3:MoS2 hybrid are slightly redshifted with the appearance of absorption peaks in the near-infrared region due to the defects created after the oxidation reaction. The composition and atomic percentages of each component in the hybrid layer as a function of reaction time have also been reported to give perspective guides for improving electronic and optoelectronic devices based on 2D-MoS2.

In organic photovoltaic (OPV) cells, besides the organic active layer, the electron-transporting layer (ETL) has a primordial role in transporting electrons and blocking holes. In planar heterojunction-OPVs (PHJ-OPVs), the ETL is called the exciton blocking layer (EBL). The optimum thickness of the EBL is 9 nm. However, in the case of inverted OPVs, such thickness is too high to permit efficient electron collection, due to the fact that there is no possibility of metal diffusion in the EBL during the top metal electrode deposition. In the present work, we show that the introduction of a thin potassium layer between the indium tin oxide (ITO) cathode and the EBL increases dramatically the conductivity of the EBL. We demonstrate that K not only behaves as a simple ultrathin layer allowing for the discrimination of the charge carriers at the cathode/organic material interface but also by diffusing into the EBL, it increases its conductivity by 3 orders of magnitude, which allows us to improve the shape of the J-V characteristics and the PHJ-inverted OPV efficiency by more than 33%. Moreover, we also show that PHJ-inverted OPVs with K in their EBLs are more stable than those with Alq(3) alone.

Y A series of trivalent lanthanide and group 3 metal coordination polymers with pyromellitic acid [M (Hbtec)](n) (M = Eu, Dy, Sm, Nd, Ce, Er, Y) has been synthesized and structurally characterized. Contrary to most of coordination polymers, the reported compounds do not present any crystallized solvent molecules, and consequently they are thermally stable until 400-500 degrees C. Moreover, they also exhibit good stability in water on a wide pH range. Compounds were synthesized by hydrothermal route with conventional heating but also with microwave-assisted heating, allowing to noticeably reduce the synthesis time to 1 h max. Efforts have been done to obtain nanoparticles with this strategy. Finally, the luminescence properties of the lanthanide counterparts emitting in the visible range (Dy, Sm, Eu) were thoroughly investigated, and the Eu compound exhibit good quantum yield. (C) 2021 Elsevier Ltd. All rights reserved.

A mechanochromic luminescent copper iodide cluster is reported whose luminescence is exalted in response to mechanical stress. The underlying mechanism has been investigated along with the preparation of mechanically responsive films.