Properties Of Advanced Materials Research Articles

EFFECT OF DIFFERENT ADDITIVES AND SINTERING REGIMES ON THE OPTICAL PROPERTIES OF DLP PRINTED TRANSLUCENT ALUMINA

Additive manufacturing of components with enhanced characteristics to combine the geometrical flexibility of layer-by-layer manufacturing and the remarkable thermomechanical and optical properties of advanced materials has become a focus for research in the last decades. In this investigation, in-house developed Al2O3 slurries mixed with either MgO or MgAl2O4 were digitally light processed and the resulting green parts underwent slow thermal debinding at low heating rates to produce dense and stable brown samples, which were subsequently subjected to different sintering regimes to obtain translucent samples. Air sintering trials were conducted at 1700 °C and the effect of different heating rates and holding times at the sintering temperature were investigated. In addition, vacuum sintering at 1600 °C was conducted for the best conditions to assess the effect of an oxygen-reduced atmosphere. Geometrical dimensions and density data were collected at the brown and fired stages to observe their evolution through the process with the help of high-magnification optical microscopy. Scanning electron microscope (SEM) images of the sintered samples were collected to observe and characterise the obtained microstructure. In addition, X-ray diffraction (XRD) was used to identify the crystal structure and assess the insurgence of secondary phases. Finally, total transmittance and in-line transmittance were measured to evaluate the translucency level achieved by the produced sintered samples. Translucent alumina samples exhibiting a maximum total transmittance of 90.4% and a maximum real in-line transmittance (RIT) of 16.9% in the visible and near-infrared regions were fabricated.

Long-Range Atomic Order on Double-Stepped Al2O3(0001) Surfaces.

The deterministic preparation of highly ordered single-crystalline surfaces is a key step for studying and utilizing the physical properties of various advanced materials. This paper presents the fast and straightforward preparation of vicinal Al2O3(0001) surfaces with micrometer-scale atomic order. Crisp electron-diffraction spots up to at least 20th order evidence atomic coherence on terraces with widths exceeding 1 μm. The unique combination of three properties of Al2O3(0001) underlie this remarkable coherence: its high-temperature stability; the differences in the ionic bonding systems of the surface as compared to the bulk; and the fact that the terraces are non-polar whereas the step edges have a polar character. The step edges are furthermore found to have alternating configurations, which drive a step-doubling transition. On double-stepped surfaces, the Al-rich ° surface reconstruction attains a singular in-plane orientation. These results set a benchmark for high-quality surface preparation and thus expand the scope for both fundamental studies on and the technological utilization of exciting materialsystems.

Novel MoS2-decorated Cu2O hybrid nanoparticles for enhanced non-enzymatic electrochemical cholesterol detection

Precise identification of cholesterol levels is crucial for the early diagnosis of cardiovascular risk factors. This paper presents a novel approach for cholesterol detection that circumvents the reliance on enzymatic processes. Leveraging the unique properties of advanced materials and electrochemical principles, our non-enzymatic approach demonstrates enhanced sensitivity, specificity, and limit of detection in cholesterol analysis. A non-enzymatic electrochemical biosensor for Cholesterol, employing a nanohybrid comprising Cu2O nanoparticles decorated with MoS2, is presented. The cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry techniques were employed to investigate the electrochemical behaviour of the glassy carbon electrode modified with the Cu2O/MoS2 nanohybrid. The modified electrode exhibited an excellent sensitivity of 111.74 μA μM−1 cm−2 through the CV method and showcased a low detection limit of 2.18 μM and an expansive linear range spanning 0.1–180 μM when employing the DPV method. The electrode also showed good selectivity to various interfering components in 0.1 M NaOH and a satisfied stability of about 15 days at room temperature. The study demonstrates the potential for broader applications in clinical diagnostics and monitoring cardiovascular health, paving the way for a paradigm shift in cholesterol detection methodologies and offering a more efficient and cost-effective alternative to traditional enzymatic assays.

Hook's law scaled broken-bond model for surface energy: From metals to ceramics

Innovative surfaces via lattice engineering are crucial challenges and critical to enhance the mechanical and functional properties of advanced materials. Here, a universal linear scaling rule in terms of key property parameters (KPPs) is proposed to estimate the modifications of local lattice strain (LLS) caused by the surface, in which the bulk modulus (B), the B/G ratio, and the bond energy are utilized to describe the KPPs of the BCC and FCC, the isotropic HCP, and the polarized A2B2O7-type Pyrochlore, individually. The modified broken-bond model by the Hook's law is addressed to predict the elastic-energy-corrected surface energy efficiently and precisely, which is capable to deal with the complex of geometry, chemistry, charge states of clean surface and are verified and validated in 28 metals and ceramics. While the LLS of metals is caused by the improved bond length, the ceramics one is yielded by the reduced one of polarized surface.

Effects of Topological Parameters on Thermal Properties of Carbon Nanotubes via Molecular Dynamics Simulation

Due to their unique properties, carbon nanotubes (CNTs) are finding a growing number of applications across multiple industrial sectors. These properties of CNTs are subject to influence by numerous factors, including the specific chiral structure, length, type of CNTs used, diameter, and temperature. In this topic, the effects of chirality, diameter, and length of single-walled carbon nanotubes (SWNTs) on the thermal properties were studied using the reverse non-equilibrium molecular dynamics (RNEMD) method and the Tersoff interatomic potential of carbon–carbon based on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). For the shorter SWNTs, the effect of chirality on the thermal conductivity is more obvious than for longer SWNTs. Thermal conductivity increases with increasing chiral angle, and armchair SWNTs have higher thermal conductivity than that of zigzag SWNTs. As the tube length becomes longer, the thermal conductivity increases while the effect of chirality on the thermal conductivity decreases. Furthermore, for SWNTs with longer lengths, the thermal conductivity of zigzag SWNTs is higher than that of the armchair SWNTs. Thermal resistance at the nanotube–nanotube interfaces, particularly the effect of CNT overlap length on thermal resistance, was studied. The simulation results were compared with and in agreement with the experimental and simulation results from the literature. The presented approach could be applied to investigate the properties of other advanced materials.

Machine learning assisted prediction in the discharge capacities of novel MXene cathodes for aluminum ion batteries

Conventional experimental methods are widely utilized to discover novel cathode materials for aluminum ion batteries (AIB), but their high price and low-efficiency present extra challenges when dealing with the vast family of MXene materials. In order to vigorously promote the application and development of MXene cathodes in aluminum ion batteries, a new accelerable method to predict the discharge capacities based on machine learning is proposed. Firstly, we establish and train the machine learning models which extract from experimental results of several MXene cathodes (Nb2C, Ti3C2, and V2C) to predict the battery status and initial discharge capacity of mentioned cathodes. Secondly, we refine the models using few Ti2C experimental results to successfully predict the battery status and initial discharge capacity for new Ti2C cathode, which exhibit higher capacity and longer cycle life than Nb2C, Ti3C2 and V2C cathodes. This work provides a new method for predicting electrochemical properties of advanced energy materials beyond MXene materials for aluminum-ion batteries, including but not limited to carbon materials or transition metal oxides.

Editorial: Mechanical properties of advanced materials and structures for energy absorption

Editorial: Mechanical properties of advanced materials and structures for energy absorption

Simultaneous Enhancement of Flame Resistance and Antimicrobial Activity in Epoxy Nanocomposites Containing Phosphorus and Silver-Based Additives.

The design and manufacture of innovative multifunctional materials possessing superior characteristics, quality and standards, rigorously required for future development of existing or emerging advanced technologies, is of great importance. These materials should have a very low degree of influence (or none) on the environmental and human health. Adjusting the properties of epoxy resins with organophosphorus compounds and silver-containing additives is key to the simultaneous improvement of the flame-resistant and antimicrobial properties of advanced epoxy-based materials. These environmentally friendly epoxy resin nanocomposites were manufactured using two additives, a reactive phosphorus-containing bisphenol derived from vanillin, namely, (4-(((4-hidroxyphenyl)amino)(6-oxido-6H-dibenzo[c,e][1,2]oxaphosphinin-6-yl)methyl)-2-methoxyphenyl) phenylphosphonate (BPH), designed as both cross-linking agent and a flame-retardant additive for epoxy resin; and additional silver-loaded zeolite L nanoparticles (Ze-Ag NPs) used as a doping additive to impart antimicrobial activity. The effect of BPH and Ze-Ag NPs content on the structural, morphological, thermal, flame resistance and antimicrobial characteristics of thermosetting epoxy nanocomposites was investigated. The structure and morphology of epoxy nanocomposites were investigated via FTIR spectroscopy and scanning electron microscopy (SEM). In general, the nanocomposites had a glassy and homogeneous morphology. The samples showed a single glass transition temperature in the range of 166-194 °C and an initiation decomposition temperature in the range of 332-399 °C. The introduction of Ze-Ag NPs in a concentration of 7-15 wt% provided antimicrobial activity to epoxy thermosets.

A Comprehensive and Versatile Multimodal Deep-Learning Approach for Predicting Diverse Properties of Advanced Materials.

A multimodal deep-learning (MDL) framework is presented for predicting physical properties of a ten-dimensional acrylic polymer composite material by merging physical attributes and chemical data. The MDL model comprises four modules, including three generative deep-learning models for material structure characterization and a fourth model for property prediction. The approach handles an 18-dimensional complexity, with ten compositional inputs and eight property outputs, successfully predicting 913 680 property data points across 114 210 composition conditions. This level of complexity is unprecedented in computational materials science, particularly for materials with undefined structures. A framework is proposed to analyze the high-dimensional information space for inverse material design, demonstrating flexibility and adaptability to various materials and scales, provided sufficient data are available. This study advances future research on different materials and the development of more sophisticated models, drawing the authors closer to the ultimate goal of predicting all properties of all materials.

Mesenchymal-Stromal-Cell-Conditioned Media and Their Implication for Osteochondral Regeneration.

Despite significant advances in biomedical research, osteochondral defects resulting from injury, an autoimmune condition, cancer, or other pathological conditions still represent a significant medical problem. Even though there are several conservative and surgical treatment approaches, in many cases, they do not bring the expected results and further permanent damage to the cartilage and bones occurs. Recently, cell-based therapies and tissue engineering have gradually become promising alternatives. They combine the use of different types of cells and biomaterials to induce regeneration processes or replace damaged osteochondral tissue. One of the main challenges of this approach before clinical translation is the large-scale in vitro expansion of cells without changing their biological properties, while the use of conditioned media which contains various bioactive molecules appears to be very important. The presented manuscript provides a review of the experiments focused on osteochondral regeneration by using conditioned media. In particular, the effect on angiogenesis, tissue healing, paracrine signaling, and enhancing the properties of advanced materials are pointed out.

Electronic, Structural, Optical, and Electrical Properties of CsPbX3 Powders (X = Cl, Br, and I) Prepared Using a Surfactant-Free Hydrothermal Approach

Recently, several strategies have been adopted for the cesium lead halide, CsPbX3 (X = Cl, Br, and/or I), crystal growth with a perovskite-type structure, paving the way for the further development of innovative optoelectronic and photovoltaic applications. The optoelectronic properties of advanced materials are controlled, in principle, by effects of morphology, particle size, structure, and composition, as well as imperfections in these parameters. Herein, we report a detailed investigation, using theoretical and experimental approaches to evaluate the structural, electronic, optical, and electrical properties of CsPbX3 microcrystals. The microcrystals are synthesized successfully using the hydrothermal method without surfactants. This synthetic approach also offers an easy upscaling for perovskite-related material synthesis from low-cost precursors. Lastly, in this direction, we believe that deeper mechanistic studies, based on the synergy between theory and practice, can guide the discovery and development of new advanced materials with highly tailored properties for applications in optoelectronic devices, as well as other emergent technologies.

Magnetic supercapacitors: Charge storage mechanisms, magnetocapacitance, and magnetoelectric phenomena

Pseudocapacitive (PC) materials are under investigation for energy storage in supercapacitors, which exhibit exceptionally high capacitance, good cyclic stability, and high power density. The ability to combine high electrical capacitance with advanced ferrimagnetic or ferromagnetic properties in a single material at room temperature opens an avenue for the development of advanced magnetically ordered pseudocapacitive (MOPC) materials. This review covers materials science aspects, charge storage mechanisms, magnetocapacitance, and magnetoelectric (ME) phenomena in MOPC materials. Recent studies demonstrate high PC properties of advanced ferrimagnetic materials, such as spinel ferrites and hexagonal ferrites. Of particular importance is the discovery of PC properties of perovskite-type manganites, which exhibit room temperature ferromagnetism and giant negative magnetoresistance. The coupling of high capacitance and magnetization in MOPC provides a platform for strong ME interactions. Various strategies are used for manipulation of electrical capacitance/magnetization of MOPC by a magnetic field/electrode potential. Magnetocapacitance studies show significant increase in capacitance of MOPC under the influence of a magnetic field. Moreover, the application of a magnetic field results in enhanced energy density and power density, reduction of resistance, and improvement of cyclic stability. Such findings offer a potential of a breakthrough in the development of advanced supercapacitors. High magnetocapacitance and ME phenomena are linked to the influence of magnetic fields on electrolyte diffusion, structure of electrical double layer, charge transfer resistance, and variation of conductivity and magnetization of MOPC materials, which facilitate charge/discharge behavior. Various applications of ME effect in MOPC are discussed. Moreover, advantages of magnetocapacitive MOPC are described for applications in electronic and spintronic devices, supercapacitors, and devices for magnetically enhanced capacitive deionization of water.

Temperature-Dependent Thermal Parameter Identification of Ceramic Nanorod Aerogels Composite in the Ultrahigh Temperature Environment

The identification of the thermal properties of advanced materials is of great importance in engineering application. In this work, an inverse scheme is proposed to identify the temperature-dependent thermal parameters of ceramic nanorod aerogels (CNRAs) composite in the ultrahigh temperature environment up to 1873 K. The feasibility of the proposed method is successfully tested by an analytical solution for CNRAs with known material properties. Furthermore, the temperature-dependent thermal properties of CNRAs are successfully obtained using the experimental data acquired from the heat conduction experimental testing for a CNRAs plate. Lastly, the obtained thermal properties are used to simulate an arc-heated wind tunnel (AHWT) test of a receiving satellite antenna assembly using the FEM method. The simulated temperature at measured data has a very good agreement with the experimental data. This further demonstrates the strong capability of the proposed inverse method. In summary, the proposed approach provides an important approach for the identification of nonlinear and temperature-dependent thermal properties of advanced materials.

A state-of-the-art review on advanced ceramic materials: fabrication, characteristics, applications, and wettability

Purpose The purpose of this study is to prepare a state-of-the-art review on advanced ceramic materials including their fabrication techniques, characteristics, applications and wettability. Design/methodology/approach This review paper presents the various types of advanced ceramic materials according to their compounding elements, fabrication techniques of advanced ceramic powders as well as their consolidation, their characteristics, applications and wetting properties. Hydrophobic/hydrophilic properties of advanced ceramic materials are described in the paper with their state-of-the-art application areas. Optical properties of fine ceramics with their intrinsic characteristics are also presented within. Special focus is given to the brief description of application-based manipulation of wetting properties of advanced ceramics in the paper. Findings The study of wetting/hydrophobicity/hydrophilicity of ceramic materials is important by which it can be further modified to achieve the required applications. It also makes some sense that the material should be tested for its wetting properties when it is going to be used in some important applications like biomedical and dental. Also, these advanced ceramics are now often used in the fabrication of filters and membranes to purify liquid/water so the study of wetting characteristics of these materials becomes essential. The optical properties of advanced ceramics are equally making them suitable for many state-of-the-art applications. Dental, medical, imaging and electronics are the few sectors that use advanced ceramics for their optical properties. Originality/value This review paper includes various advanced ceramic materials according to their compounding elements, different fabrication techniques of powders and their consolidation, their characteristics, various application area and hydrophobic/hydrophilic properties.

Femtosecond laser processing of advanced technical materials

Ultra-short pulsed laser ablation may be used for high-precision machining with very low thermal influence on the processed materials. Due to this reason, lasers are increasingly used for processing of advanced materials, such as titanium alloys, nickel-based alloys or steel, every year. In this study, four advanced technical materials were analysed and compared under femtosecond laser irradiation with three different wavelengths. The main laser-material interaction parameters were identified, namely the ablation threshold and removal efficiency parameters. Higher removal rates were found for Ti6Al4V alloy with all three harmonic wavelengths. To increase process productivity, a method of increasing the repetition rate and scanning speed was presented. With the maximum repetition rate, the productivity increased five-fold with a similar removed depth and surface quality. Finally, the suitability of the identified parameters with regard to quality and productivity was demonstrated for fabrication of two complex structures – honeycomb and dot – which has the potential to improve friction properties of advanced materials.

A perspective on the Langmuir adsorption model applied to molecular liquid crystals containing ions and nanoparticles

Electrical properties of molecular liquid crystals doped with nanomaterials have been extensively studied over the past two decades. In general, nanoparticles in liquid crystals can play a dual role acting as either ion capturing agents or ion generating objects. An interplay between ions and nanomaterials in liquid crystals can result in a great variety of nontrivial ionic effects. This perspective discusses the Langmuir adsorption model applied to describe ionic phenomena in molecular liquid crystals doped with nanoparticles. The applicability and limitations of this model are emphasized. Within a range of its applicability, the Langmuir adsorption model can be used to obtain a wealth of information about nanoparticle-induced ionic effects in molecular liquid crystals. In addition, this model also offers important improvements to standard experimental procedures for evaluation of electrical properties of advanced liquid crystal materials.

Improving experimental procedures for assessing electrical properties of advanced liquid crystal materials

ABSTRACT Electrical measurements of liquid crystals are a standard part of their material characterisation. Typically, such measurements are carried out using a sandwich-like cell of a single thickness. In this paper, we show that interactions between ions and substrates of a liquid crystal cell result in the dependence of the direct current electrical conductivity of liquid crystal materials on the cell thickness. The obtained experimental results combined with modelling point to the existence of ions of several types and to the competition between ion-releasing and ion-trapping processes in liquid crystal cells. We also propose to use a multi-electrode twin-cell that allows the visualisation of the electric field screening effect in liquid crystals and its mitigation by means of ferroelectric nanoparticles.

Scattering-type Scanning Near-Field Optical Microscopy of Polymer-Coated Gold Nanoparticles.

Scattering-type scanning near-field optical microscopy (s-SNOM) has emerged over the past years as a powerful characterization tool that can probe important properties of advanced materials and biological samples in a label-free manner, with spatial resolutions lying in the nanoscale realm. In this work, we explore such usefulness in relationship with an interesting class of materials: polymer-coated gold nanoparticles (NPs). As thoroughly discussed in recent works, the interplay between the Au core and the polymeric shell has been found to be important in many applications devoted to biomedicine. We investigate bare Au NPs next to polystyrenesulfonate (PSS) and poly(diallyldimethylammonium chloride) (PDDA) coated ones under 532 nm laser excitation, an wavelength matching the surface plasmon band of the custom-synthesized nanoparticles. We observe consistent s-SNOM phase signals in the case of bare and shallow-coated Au NPs, whereas for thicker shell instances, these signals fade. For all investigated samples, the s-SNOM amplitude signals were found to be very weak, which may be related to reduced scattering efficiency due to absorption of the incident beam. We consider these observations important, as they may facilitate studies and applications in nanomedicine and nanotechnology where the precise positioning of polymer-coated Au NPs with nanoscale resolution is needed besides their dielectric function and related intrinsic optical properties, which are also quantitatively available with s-SNOM.

First-principles study of the impact of chemical doping and functional groups on the absorption spectra of graphene

The rational design of the electronic band structures and the associated properties (e.g. optical) of advanced materials has remained challenging for crucial applications in optoelectronics, solar desalination, advanced manufacturing technologies, etc. In this work, using first-principles calculations, we studied the prospects of tuning the absorption spectra of graphene via defect engineering, i.e. chemical doping and oxidation. Our computational analysis shows that graphene functionalization with single hydroxyl and carboxylic acid fails to open a band gap in graphene. While single epoxide functionalization successfully opens a bandgap in graphene and increases absorptivity, however, other optical properties such as reflection, transmission, and dielectric constants are significantly altered. Boron and nitrogen dopants lead to p- and n-type doping, respectively, while fluorine dopants or a single-carbon atomic vacancy cannot create a significant bandgap in graphene. By rigorously considering the spin-polarization effect, we find that titanium, zirconium, and hafnium dopants can create a bandgap in graphene via an induced flat band around the Fermi level as well as the collapse of the Dirac cone. In addition, silicon, germanium, and tin dopants are also effective in improving the optical characteristics. Our work is important for future experimental work on graphene for laser and optical processing applications.

Carbon Nanotube Composites with Bottlebrush Elastomers for Compliant Electrodes.

Wearable electronics and biointerfacing technology require materials that are both compliant and conductive. The typical design strategy exploits polymer composites containing conductive particles, but the addition of a hard filler generally leads to a substantial increase in modulus that is not well-matched to biological tissue. Here, we report a new class of supersoft, conductive composites comprising carbon nanotubes (CNT) embedded in bottlebrush polymer networks. By virtue of the bottlebrush polymer architecture, these materials are several orders of magnitude softer than comparable composites in the literature involving linear polymer networks. For example, a CNT content of 0.25 wt % yields a shear modulus of 66 kPa while maintaining a typical conductivity for a CNT composite (ca. 10-2 S/m). An added benefit of this bottlebrush matrix chemistry is the presence of dynamic polyester bonds that facilitate thermal (re)processing. This unique strategy of designing soft composites provides new opportunities to tailor the structure and properties of sustainable advanced materials.