Lamellar Structure Research Articles

Pickering stabilization of water-in-crude oil emulsions by paraffin wax crystals: Insights from X-ray scattering

Previous studies suggest asphaltenes are active materials at the oil-water interface, affecting the formation and stability of crude oil emulsions. However, even oils of low asphaltene content generate stable emulsions, indicating the involvement of other oil fractions. Due to the role of paraffin waxes as Pickering stabilizers or gel network formers in emulsions from other applications, this study explores their stabilization capacity in water-in-oil (W/O) emulsions and their interaction with other fractions with interfacial activity. The extraction and physicochemical characterization of paraffin waxes from two Brazilian crude oils allowed us to correlate their properties with the emulsification of both crude and model oils. Removal of asphaltenes enhances emulsion stability. Emulsion preparation with crude oils without waxes and asphaltenes demonstrates the participation of other amphiphilic components in emulsion formation, whereas waxes are necessary for their stabilization. Experiments with emulsions formed by a model oil confirmed the combined action of waxes and an amphiphilic material in the formation and stabilization of the interfacial film. However, the combination of waxes and asphaltenes are ineffective. Small-angle X-ray scattering (SAXS) analysis revealed that waxes only form a lamellar structure when highly purified, suggesting Pickering stabilization rather than the formation of a gel network. In conclusion, polar oil fractions other than asphaltene play a crucial role in emulsion formation, whereas paraffin wax provides Pickering stabilization, even beyond the wax appearance temperature (WAT). This study enhances our understanding of the mechanisms governing waxy Brazilian crude oil emulsions.

Enhancement of mechanical properties and oxidation resistance of TiAl alloy with addition of Nb and Mo alloying elements

In this study, small button-shaped ingots were prepared by a non-self-consuming vacuum arc melting method. The effect of the content of Nb and Mo elements on the microstructure, mechanical properties and oxidation resistance of TiAl alloys were investigated. The as-cast TiAl alloy presented laminar microstructure. When only adding Nb element, a small amount of β phase was distributed in the form of dots at the grain boundaries of α2/γ lamellar structure. When adding both Mo and Nb, the precipitated β phase started to precipitate in lines inside the α2/γ lamellar structure. The microhardness of the alloy increased with the increasing Nb and Mo content. The compressive strength of the alloys increased firstly with the increasing Nb content and decreased when the content of Nb exceeded 7 wt%. However, with the addition of Mo, the compressive strength of the alloys decreased drastically. The optimal compressive strength of the alloy, i.e. 2250 MPa, was obtained with 5 wt% Nb and 5 wt% Mo addition. The oxidation resistance of the alloys were enhanced with the addition of Nb and Mo elements and the TiAl–5Nb–5Mo alloy also showed the best oxidation resistance at 800 °C.

An integrated model of the human cornea as a linear biaxial birefringent medium

A novel model of human corneal birefringence is presented. The cornea is treated as a homogeneous biaxial linear birefringent medium in which the values of the binormal axes angle and organization of the main refractive indices vary continuously from the apex to the limbus. In its central part, the angle between binormal axes is 35°, and para centrally, it smoothly increases to 83.7°. The values of the main refractive indices (nx, ny, nz) change, as well as their order, from nx < nz < ny to nz < nx < ny. The transition between these two states was described with a normal distribution (μ = 0.45, σ = 0.1). The presented model corresponds with the experimental results presented in the literature. To our knowledge, it is the first model that presents the anisotropic properties’ distributions of the entire cornea. The presented model facilitates a better understanding of the corneal birefringence phenomenon directly related to its lamellar structure.

High-entropy strategy for high-temperature broadband infrared radiation and low thermal conductivity

Developing high-performance infrared radiation ceramic materials with desired broadband emissivity while reducing thermal conductivity to prevent heat transfer is highly desirable for emerging industrial and aerospace applications. Nevertheless, it remains a grand challenge to simultaneously meet these requirements in existing infrared radiation ceramic materials. Herein, a high-entropy strategy is employed to enhance the high-temperature infrared radiation property with a high emissivity above 0.9 at room temperature and 0.68 at 1200 °C across the entire range of wavelength (1–14 μm), and integrate a low thermal conductivity (<0.88 W m−1 K−1 at 1000 °C) and remarkable mechanical properties. High-entropy rare earth (RE) disilicates ((Y0.4Yb0.4Tm0.1Lu0.05Ho0.05)2Si2O7) ceramic coating with high lattice entropy has a more complex electronic structure, inducing lattice distortion and extra multi-mode vibrations, which boosts the emissivity in mid-infrared range (3–14 μm). Meanwhile, the high-entropy strategy prompts the formation of impurity energy levels as gap states, achieving optical absorption at low photon energies, and thus enhancing the emissivity in near-infrared range (1–3 μm). Simultaneously, (Y0.4Yb0.4Tm0.1Lu0.05Ho0.05)2Si2O7) ceramic coating owns diffusion-mediated thermal transport properties with strong phonon scattering, assisted further by the lamellar porous structure, thereby enabling a low thermal conductivity. The excellent mechanical properties ensure the reliability of the coating in extreme environments. All these merits render the high-entropy ceramic coating competitive for the development of high-temperature broadband high-emissivity thermal radiation materials.

Layered structure of sialoliths compared with tonsilloliths and antroliths.

The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro- CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

Heterogeneous Microstructure and Tensile Properties of an Austenitic Stainless Steel

Stainless steel (SS) exhibits excellent ductility; however, its low strength hinders its practical applications. To achieve good synergy between strength and ductility, a heterogeneous structure was introduced into a newly developed nitrogen-alloyed low-nickel austenitic steel, QN1803. The received QN1803 was cold-rolled and annealed at 993 K for different durations, and the microstructural evolution and tensile mechanical properties were investigated. The yield strength (1130 MPa) of the QN1803 annealed at a temperature of 993 K for 15 min was approximately three times higher than that of the as-received sample (314 MPa). The short annealing time of 15 min yielded a heterogeneous structure with grain size distributions ranging from nanoscale to micron-scale. The annealed QN1803 exhibited typical dislocation cells and dislocation walls caused by slipping after cold rolling. During annealing, a step-like lamellar structure is formed. The high yield strength was obtained from the large number of twins and hard ultrafine grains. The good ductility is due to the large number of dislocations generated in the soft grains and the GNDs around the heterogeneous interfaces. Additionally, the lamella structure of the material also contributes to improved ductility to a certain degree. The aim of this paper is to develop new materials with both high yield strength and excellent toughness based on more economical materials cost.

Metal–Organic Framework‐Derived MnO/C Nanocomposite with Lamellar Porous Structure for High‐Performance Aqueous Zinc‐Ion Battery

Manganese oxide (MnO) is a promising cathode for aqueous zinc‐ion batteries; however, issues such as low electrical conductivity, Mn2+ dissolution, and sluggish kinetics lead to poor electrochemical performance that block its commercialized application. Herein, the first utilization of Mn‐based metal–organic frameworks synthesized from manganese salt and 1,2,4,5‐benzenetetracarboxylic acid to fabricate MnO/C composite materials is presented. The analysis of electrochemical testing demonstrates that carbon‐coated MnO can effectively promote electrochemical properties compared to the pure MnO. Additionally, the Zn2+/Mn2+ concentration is optimized in order to maximize the electrode's potential in terms of electrochemical performance. The MnO/C‐600 electrode delivers a higher specific capacity of 322 mAh g−1 at 0.1 A g−1 and exhibits a capacity of 270 mAh g−1 after 360 cycles at 0.5 A g−1 in the 2.0 m ZnSO4 + 0.2 m MnSO4 system. The results also indicate that the MnO/C‐600 electrode has higher diffusion coefficients, and its unique structure improves structural stability and ion/electron transfer. Furthermore, the energy storage mechanism of the MnO/C‐600 electrode is investigated. Herein, a method is provided for preparing an inexpensive and convenient MnO/C cathode for high‐performance aqueous zinc‐ion batteries.

Economical and shape-stabilized hydrated salt/bagasse biomass-derived carbon phase change composite for thermal energy storage

Due to their high heat storage density, low cost, and non-inflammability, hydrated salts have significant potential for application in thermal energy storage for buildings. Hydrated salts, however, have a few drawbacks, including high supercooling degree, unstable shape, and phase separation. In general, materials such as graphite, aerogel, and foam metal are commonly used to provide support for hydrated salts in order to mitigate or eliminate their drawbacks. While these currently used supporting materials have expensive and complicated production procedures. In this study, we developed bagasse biomass-derived carbon (BBC) materials to obtain easily accessible, cost-effective, and environmentally friendly support materials. Using the high-temperature carbonization method, the bagasse made from biological waste displayed a highly oriented and stacked lamellar structure. This not only significantly lowered the cost but also made the storage of hydrated salts easier. A straightforward vacuum impregnation technique was used to create SSD-SC/BBC phase change composites (PCCs). In comparison to sodium sulfate decahydrate (SSD), the developed SSD-SC/BBC9 PCCs exhibited a higher thermal storage capacity of 161.5 J/g, along with an exceptionally low supercooling degree. They also demonstrated the higher thermal conductivity of 1.79 W·m−1·K−1, improved thermal reliability, and enhanced solar-thermal energy conversion ability. Compared to other support materials, the economic analysis using static and dynamic payback periods demonstrates that the utilization of biomass-derived carbon as a support material for phase change materials (PCMs) is cost-effective, with lower preparation costs and a shorter payback period. A simple, affordable, and environmentally friendly method for utilizing hydrated salts in thermal energy storage for buildings is provided by SSD-SC/BBC9 PCCs.

Nb2CTx MXene coating with inhibition of oxidative stress prepared by Marangoni effect for hemodialysis therapy

Oxidative stress is an important risk factor for end-stage renal disease (ESRD), that can further aggravate the disease during dialysis of patients and eventually lead to various complications. Here, Nb2CTx MXene was deposited using the Marangoni force to tightly stack them on the polyvinylidene fluoride (PVDF) substrate membrane, conferring the alleviation of oxidative stress. Owing to the excellent antioxidant activity of Nb2CTx MXenes, PVDF/Nb2CTx membranes can scavenge a wide range of reactive oxygen species (ROS) to inhibit advanced glycation end-products (AGEs). Additionally, the functionalized membranes modulated the intracellular antioxidant enzyme activity and maintained an intracellular oxidative-antioxidant system balance. In the simulated dialysis experiment, the optimised hemodialysis membrane (MMX-0.2 membrane) exhibited the high clearance of middle and small uraemic toxins (72.6% of lysozyme and 90.0% of urea) owing to the unique lamellar structure of Nb2CTx. Protein adhesion experiments showed that Nb2CTx MXenes improved membrane hydrophilicity and hindered protein adsorption. The functionalized membranes exhibited excellent hemocompatibility and cytocompatibility, meeting the biocompatibility requirements for hemodialysis membranes. In this work constructed PVDF/Nb2CTx functionalized membranes with excellent oxidative stress inhibition and high dialysis performance are proposed as a novel hemodialysis membrane preparation method to improve patient prognosis.

Sustainable golden nanoflowers grafted food-waste derived biotemplate for the direct SERS-detection of carcinogenic herbicides from agro-farms

Surface Enhanced Raman Scattering (SERS) is emerging as a potent analytical tool for the detection of various pollutants in complex environments due to its distinctive vibrational fingerprint ability and pronounced detection sensitivity. Precautious of adverse blue-green economies and ecological impacts, sustainable generation of SERS active substrates and analyte casting matrices are getting prioritized. Herein, gold nanoflowers (AuNFs) of ∼75 ± 15 nm were initially biofabricated using an expended cell culture medium as a one-step synthesis cum stabilization strategy. Then the heavy architecture of multi-faceted AuNFs with deep pits and edges, that acted as hotspots for enhancing the localized electromagnetic fields, was utilized for the direct SERS detection of commonly used carcinogenic herbicides collected from agro-farms at nanomolar regimes with 0.44 ppm and 0.27 ppm for Glyphosate and amino methyl phosphonic acid, respectively. Such a low level detection is superior by 8.33% when compared to the reported values. Computational finite-difference time-domain (FDTD) simulations affirmed the enhanced SERS effect from the multi-faceted nanostructure of AuNFs with structural heterogeneities that provide numerous hotspots to amplify the localized electromagnetic field. More eminently, fish scale derived biotemplate through AuNF-analyte drop casting contributed to the exceptional intensities, attributed to the naturally grooved hierarchically porous hydrophilic lamellar structures contact angle of 73°. Overall, the adapted bioengineering of SERS substrate is safe, robust, affordable and reproducible, fostered by bioderived durable biomatrix offering potent sustainable SERS detection of various biomedically and environmentally relevant molecules.

Isomorphic Insertion of Ce(III)/Ce(IV) Centers into Layered Double Hydroxide as a Heterogeneous Multifunctional Catalyst for Efficient Meerwein-Ponndorf-Verley Reduction.

The development of highly active acid-base catalysts for transfer hydrogenations of biomass derived carbonyl compounds is a pressing challenge. Solid frustrated Lewis pairs (FLP) catalysis is possibly a solution, but the development of this concept is still at a very early stage. Herein, stable, phase-pure, crystalline hydrotalcite-like compounds were synthesized by incorporating cerium cations into layered double hydroxide (MgAlCe-LDH). Besides the insertion of well-isolated cerium centers surrounded by hydroxyl groups, the formation of hydroxyl vacancies near the aluminum centers, which were formed by the insertion of cerium centers into the layered double hydroxides (LDH) lattice, was also identified. Depending on the initial cerium concentration, LDHs with different Ce(III)/Ce(IV) ratios were produced, which had Lewis acidic and basic characters, respectively. However, the acid-base character of these LDHs was related to the actual Ce(III)/Ce(IV) molar ratios, resulting in significant differences in their catalytic performance. The as-prepared structures enabled varying degrees of transfer hydrogenation (Meerwein-Ponndorf-Verley MPV reduction) of biomass-derived carbonyl compounds to the corresponding alcohols without the collapse of the original lamellar structure of the LDH. The catalytic markers through the test reactions were changed as a function of the amount of Ce(III) centers, indicating the active role of Ce(III)-OH units. However, the cooperative interplay between the active sites of Ce(III)-containing specimens and the hydroxyl vacancies was necessary to maximize catalytic efficiency, pointing out that Ce-containing LDH is a potentially commercial solid FLP catalysts. Furthermore, the crucial role of the surface hydroxyl groups in the MPV reactions and the negative impact of the interlamellar water molecules on the catalytic activity of MgAlCe-LDH were demonstrated. These solid FLP-like catalysts exhibited excellent catalytic performance (cyclohexanol yield of 45%; furfuryl alcohol yield of 51%), which is competitive to the benchmark Sn- and Zr-containing zeolite catalysts, under mild reaction conditions, especially at low temperature (T = 65 °C).

Strength and ductility improvement of the axial gradient microstructure TC21 titanium alloys manufactured by electropulsing plus step-quenching treatment

In order to reduce the weak area caused by traditional connection method and improve the structural efficiency of aircraft, the design concept of an integral component with dual microstructure is proposed. The electropulsing treatment (EPT) was used to produce an axial gradient microstructure (AGM) in TC21 titanium alloy, followed by the step-quenching treatment (SQT) to tailor the precipitation behavior of the α phase. Results demonstrate that the AGM produced by the combination of EPT and SQT achieves a simultaneous enhancement in both strength and plasticity of the alloy. Compared to EPT alone, the SQT results in the dissolution of the bimodal microstructure region with small-sized α phase, and an increased density of secondary α phase precipitation in both the transition and lamellar microstructure regions. During room temperature tensile deformation, coordinated distribution of deformation occurs sequentially in various regions, the 101̅0112̅0type of prismatic slip and deformation nanotwins exist in the equiaxed and lamellar α phase, respectively. Moreover, the deformation gradually declines from the bimodal region to the lamellar region, leading to the fracture of AGM in the bimodal region and an overall augmentation of the strength and plasticity of TC21 alloy. Hence, the results of this paper can provide research basis for the strength and plasticity improvement and deformation damage mechanism of high strength and toughness titanium alloy.

Additive manufacturing and joining double processes of ceramic-resin green bodies using a single- or double-phase photocuring slurry

The present work focuses on a double process involving additive manufacturing and joining of ceramic-resin green bodies, aiming to overcome the challenges of printing long-span and large-size ceramic specimens. Through partitioned 3D printing, individual green bodies were built and then joined together using either a single-phase slurry (Al2O3) or a double-phase slurry (Al2O3 and ZrO2). The impact of sintered temperature, photocuring duration time, and sandwich layer thickness on the three-point bending strength of the joined specimens was investigated. The analysis of photocuring depth, thermogravimetry, and composition structure characteristics reveals two significant joining mechanisms, namely initial polymer network joining and ultimate grain bonding and growth joining, which play a crucial role in holding the connection shapes and enhancing the connection strength. Furthermore, the bending strength analysis indicates a positive correlation between sintering temperature and bending strength, while a negative correlation is observed between sandwich layer thickness and bending strength. The photocuring duration time has no significant impact on the bending strength. Finally, the double-phase slurry demonstrates superior connection performance, but the joining strength is decreased to 44.53 % of the sintered substrate specimens due to the presence of joining defects such as flow channel pores and lamellar gaps. These defects have prompted the development of lamellar structures, flow channel pores, and intercrystalline fracture regions, consequently reducing the overall strength.

High performance mixed-dimensional assembled MXene composite membranes for molecular sieving

Two-dimensional (2D) separation membranes have proved their superiorities in addressing global water scarcity and recycling resources. However, current 2D membranes usually suffer from swelling and irregular stacking issues, which result in poor separation performance. Herein, we developed novel mix-dimensional assembled MXene composite membranes with high permeability and selectivity by intercalating 1D carboxylated cellulose nanofibers (CNFs) into 2D lamellar MXene nanosheets. The effects of chain length of CNFs and MXene/CNFs mass ratios on the morphologies, physicochemical properties, and separation performances of composite membranes were systematically investigated. The optimized MXC-3-L membrane exhibited superior rejection to Congo red (CR, >99%) and remarkable separation efficiency of dye/salt. The separation factors for the CR/NaCl and CR/Na2SO4 mixtures were 512.0 and 517.2, respectively. Moreover, the MXC-3-L membrane showed distinct rejections to perfluoroalkyl substances (PFAS) (>95%) with a nearly 8-fold increase of permeance in comparison with the commercial polyamide membrane. The 2D X-ray diffraction analysis verified that the intercalation of 1D CNFs into 2D MXene nanosheets via strong hydrogen bonding can regulate the nanochannel into more stable and regularly stacking lamellar structures, which plays a key role in high permeance and excellent molecular separation efficiency. In addition, 1D CNFs play an essential role as “threading” and “stitching”, shielding the defects between adjacent MXene nanosheets and improving the separation efficiencies. Our work provides new insights into design of defect-free and highly selective 2D materials-based membranes for enhanced wastewater treatment and molecular sieving.

Liquid-Liquid interfacial approach for rapid synthesis of Well-Crystalline Two-Dimensional Metal-Organic frameworks for nitro reduction

Two-dimensional metal–organic frameworks (2D MOFs) have garnered significant attention due to their exceptional properties across diverse research domains, including catalysis, biomedicine, gas adsorption, separation, energy storage, and sensing. Despite these promising attributes, the facile and large-scale synthesis of 2D MOFs with high crystallinity remains a formidable challenge. In this study, we propose a novel approach based on a modified liquid–liquid interfacial method for the rapid synthesis of well-crystalline 2D MOFs. By vigorously mixing water, a hydrophobic solvent, and an emulsifier, we generate micrometer-sized droplets that create substantial curved two-phase interfaces. This method is compatible with various ligands and metal ions, enabling the rapid formation of 2D MOFs at these curved interfaces under additional pressure. The subsequent separation of oil and water phases via centrifugal force promotes moderate π-π stacking within the 2D MOF, thereby stabilizing the lamellar structure and enriching the material at the two-phase interface. Remarkably, the entire synthesis process requires a mere 3 min, yielding grams of product in a single run. Furthermore, solvent reuse does not compromise the quality of the resulting 2D MOFs. As a practical application, we synthesized phthalocyanine (Pc)-based structures using this method for the catalytic reduction of nitroaromatics. Among these, Cu-CoPc (2D MOFs with Cu2+ coordinated to CoPc) emerged as the most active catalyst, achieving a turnover frequency (TOF) value of 4726 h−1 for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Notably, this TOF value surpasses that of non-precious catalysts and is 180 times higher than that of commercial Pd/C (10 wt%).

Structural control of corneal transparency, refractive power and dynamics.

The cornea needs to be transparent to visible light and precisely curved to provide the correct refractive power. Both properties are governed by its structure. Corneal transparency arises from constructive interference of visible light due to the relatively ordered arrangement of collagen fibrils in the corneal stroma. The arrangement is controlled by the negatively charged proteoglycans surrounding the fibrils. Small changes in fibril organisation can be tolerated but larger changes cause light scattering. Corneal keratocytes do not scatter light because their refractive index matches that of the surrounding matrix. When activated, however, they become fibroblasts that have a lower refractive index. Modelling shows that this change in refractive index significantly increases light scatter. At the microscopic level, the corneal stroma has a lamellar structure, the parallel collagen fibrils within each lamella making a large angle with those of adjacent lamellae. X-ray scattering has shown that the lamellae have preferred orientations in the human cornea: inferior-superior and nasal-temporal in the central cornea and circumferential at the limbus. The directions at the centre of the cornea may help withstand the pull of the extraocular muscles whereas the pseudo-circular arrangement at the limbus supports the change in curvature between the cornea and sclera. Elastic fibres are also present; in the limbus they contain fibrillin microfibrils surrounding an elastin core, whereas at the centre of the cornea, they exist as thin bundles of fibrillin-rich microfibrils. We present a model based on the structure described above that may explain how the cornea withstands repeated pressure changes due to the ocular pulse.

Homogenization of 3D laminated micro-structures including bending effects

In this paper, a homogenization method which captures intrinsic size effect associated with fiber diameter is revisited and adapted for three-dimensional laminated micro-structures. Based on a unit-cell composed of matrix and reinforcement layers, enhanced deformation gradients varying through the thickness, are introduced with the aid of an additional kinematic variable reflecting the difference between the homogenized and constituent level deformation gradients. In the current work, as opposed to the original formulation, higher order terms are preserved for both phases and therefore bending stiffness of the matrix phase can be taken into account as well. The formulation is implemented within the commercial finite element solver Abaqus through user element (UEL) subroutine considering a finite strain hyperelastic response for the reinforcement layers and a von Mises type hyper-elastoplastic one for the matrix phase. Explicitly discretized unit-cells with varying reinforcement phase fraction, layer inclination angle and layer thicknesses are used as references to assess the predictive capabilities of the homogenized model and the significance of bending stiffness of the phases. Similarly, explicitly discretized model of a beam type structure with a crossed lamellar micro-structure is used to evaluate the performance of the homogenized model under more general, non-periodic boundary conditions. The findings of both cases support the effectiveness of the homogenized model.

Photoluminescent Self-Healable Waterborne Polyurethane/Mo and S Codoped Graphitic Carbon Nitride Nanocomposite with Bioimaging and Encryption Capability.

Creating polymers that combine various functions within a single system expands the potential applications of such polymeric materials. However, achieving polymer materials that possess simultaneously elevated strength, toughness, and self-healing capabilities, along with special properties, remains a significant challenge. The present study demonstrates the preparation of S and Mo codoped graphitic carbon nitride (g-C3N4) (Mo@S-CN) nanohybrid and the fabrication of self-healing waterborne polyurethane (SHWPU)/Mo@S-CN (SHWPU/NS) nanocomposites for advanced applications. Mo@S-CN is an intriguing combination of g-C3N4 nanosheets and molybdenum oxide (MoOx) nanorods, forming a complex lamellar structure. This unique arrangement significantly improves the inborn properties of SHWPU to an impressive degree, especially mechanical strength (28.37-34.11 MPa), fracture toughness (73.65-140.98 MJ m-2), and thermal stability (340.17-348.01 °C), and introduces fluorescence activity into the matrix. Interestingly, a representative SHWPU/NS0.5 film is so tough that a dumbbell of 15 kg, which is 53,003 times heavier than the weight of the film, can be successfully lifted without any significant crack. Remarkably, fluorescence activity is developed because of electronic excitations occurring within the repeating polymeric tris-triazine units of the Mo@S-CN nanohybrid. This fascinating feature was effectively harnessed by assessing the usability of aqueous dispersions of the Mo@S-CN nanohybrid and photoluminescent SHWPU/NS nanocomposites as sustainable stains for bioimaging of human dermal fibroblast cells and anticounterfeiting materials, respectively. The in vitro fluorescence tagging test showed blue emission from 365 nm excitation, green emission from 470 nm excitation, and red emission from 545 nm excitation. Most importantly, in vitro hemocompatibility assessment, in vitro cytocompatibility, cell proliferation assessment, and cellular morphology assessment supported the biocompatibility nature of the Mo@S-CN nanohybrid and SHWPU/NS nanocomposites. Thus, these materials can be used for advanced applications including bioimaging.

Phase Formation during the Synthesis of the MAB Phase from Mo-Al-B Mixtures in the Thermal Explosion Mode.

This work focused on the production of the MoAlB MAB phase through self-propagating, high-temperature synthesis in the thermal explosion mode. The influence of the method of a Mo-Al-B-powder reaction mixture preparation on the combustion temperature, mechanism, and stages of the MAB phase formation in the combustion process was investigated. The combustion temperatures of the mixtures obtained in the rotary ball mill and high-speed planetary ball mill were 1234 and 992 °C, respectively. The formation of intermediate compounds Mo3Al8 and α-MoB in the combustion front, along with MoAlB, was established using the time-resolved X-ray diffraction method. In the case of the mixture prepared in a ball mill, the primary interaction in the combustion front occurred through the Al melt, and in the case of using a planetary mill, solid-phase reactions played an important role. The mechanical activation of the mixture in a planetary mill also accelerated the processes of phase formation. The method of a reaction mixture preparation has virtually no effect on the MoAlB MAB phase content in combustion products (92-94%), but it does affect their structure. The synthesis products have a lamellar structure composed of MAB grains with a thickness of ~0.4 μm and a length of ~2-10 μm.

Making high primary α phase content titanium alloy exceptional strength and ductility by designing the heterogeneous structure

As a challenge to avoid the strength-ductility trade-off for Ti alloys, strength and ductility are contradictory, especially at a high content of primary α phase. This study proposed a new strategy to evade this trade-off dilemma by designing an 81% primary α phase/ultrafine-grained (UFG) secondary α phase lamellar heterogeneous structure(LPSlow-HS) in near-α Ti alloys. Compared to the bimodal structure, the LPSlow-HS offers a remarkable increase in the ultimate tensile strength(1119 MPa) and yield strength(1069 MPa), respectively, while the elongation (15%) is not sacrificed. Owing to the strong heterogeneous deformation-induced(HDI) strengthening, more number of delamination of interfaces, UFG microstructures and strong strain hardening render the Ti alloys high strength. This strategy may provide a new approach for achieving higher HDI strengthening effects in heterogeneous structures (HS) under high soft phases, and offer a feasible method for producing high strength-ductility Ti alloys under high primary α phase.