Sodium Silicate Glasses Research Articles

Synthesis and application of WO3/PVA nano composite for antibacterial and thermal insulation

Abstract Insulation of glass material is very important for sustainable environment in this real world without compromising its primary function. The aim of this research is to provide robust solution by synthesis the Nano Tungsten trioxide particles via the chemical precipitation method. Developed WO3 NPs Characterized by using x-ray diffraction for; crystal structure, compound composition, and average crystalline size. Scanning Electron Microscopy (SEM) employed to analyze the shape and dimensions of the WO3 NPs. Explored the potential thermal insulation and antibacterial attributes by coating 1%, 3%, 5% and 7% concentration of synthesized WO3 NPs in polyvinyl alcohol onto a sodium silicate glass substrate (4 × 4 inches; 2 mm thickness) by using 50 μm doctor blade. WO3/PVA solution showed the antibacterial properties measure by agar disc diffusion method on gram positive and negative bacterial culture S. coli and E. bacterial culture and the obtained results after incubation were showing very minor zone of incubation as compare to previous studies. Thermal insulation of coated glass samples were increased with % of WO3 NPs concentration in PVA and validate by significant coefficient of determination (R2 = 0.985).

Pressure-induced structural variations and mechanical behavior of silicate glasses: Role of aluminum and sodium

This study investigates the effects of pressure-induced densification on the structural and mechanical properties of albite-like (12.5 % Na2O·12.5 % Al2O3·75 % SiO2) and sodium silicate (12.5 % Na2O·87.5 % SiO2) glasses using Molecular Dynamics simulations. Densification increased the coordination numbers of Al and Na, facilitated Al-O-Al clustering and formation of three-bridging oxygens, reduced T-O-T angles, and packed sodium ions in albite glass. Sodium silicate glass exhibited densification primarily through increased Na coordination, reduction of Si-O-Si angle and reduced Na-Na distances. Elastic modulus calculations revealed increased stiffness with densification due to enhanced atomic packing and glass reticulation. Uniaxial tensile tests showed densified glasses had higher ductility and strength than undensified counterparts, highlighting the positive effects of pressure-induced structural rearrangements. Hydrostatic compression tests demonstrated reversible densification under varying pressure loads, with pre-treatment conditions significantly affecting residual densification.

Thermal conductivity in modified sodium silicate glasses is governed by modal phase changes.

The thermal conductivity of glasses is well-known to be significantly harder to theoretically describe compared to crystalline materials. Because of this fact, the fundamental understanding of thermal conductivity in glasses remain extremely poor when moving beyond the case of simple glasses, e.g., glassy SiO2, and into so-called "modified" oxide glasses, that is, glasses where other oxides (e.g., alkali oxides) have been added to break up the network and alter, e.g., elastic and thermal properties. This lack of knowledge is apparent despite how modified glasses comprise the far majority of known glasses. In the present work, we study an archetypical series of sodium silicate [xNa2O-(100 - x)SiO2] glasses. Analyses of modal contributions reveal how increasing Na2O content induces increasing vibrational localization with a change of vibrations to be less ordered and a related general decrease in modal contributions to thermal conductivity. We find the vibrational phases (acoustic vs optical) of sodium vibrations to be relatively disordered compared to the network-forming silicon and oxygen species, explaining how increasing Na2O content decreases thermal conductivity. Our work sheds new light on the fundamentals of glassy heat transfer as well as the interplay between thermal conduction and modal characteristics in glasses.

Wave vector dependence of x-ray beam induced dynamics in sodium silicate glasses

Wave vector dependence of x-ray beam induced dynamics in sodium silicate glasses

Correlation effect and sodium diffusion in silicate glass: molecular dynamics simulation

We conducted a molecular dynamics simulation to investigate the diffusion in sodium silicate glass. The result shows that the sodium diffusion is accompanied with the correlation effect that Na atoms often leave and then return to the starting polyhedron. We establish the expression for diffusion constant D via hopping rate γ, correlation factor F and average square distance per visiting polyhedron d2. The results show that unlike diffusion in crystal, F decreases with decreasing temperature. Moreover, F is dependent with SiO2 content of glass, and D exhibits a linear dependence on the product Fγ.

Tailoring Optical Bandpass Filters in Sodium Silicate Glass: Impact of CuO Incorporation

Tailoring Optical Bandpass Filters in Sodium Silicate Glass: Impact of CuO Incorporation

Synthesis and Optical Properties of Erbium-Doped Sodium Silicate in Sol-Gel Matrix

In this study, we investigated how the concentration of erbium (0.0, 1, 2 mol% Er) affects the structural and optical properties of thin films made from sol-gel sodium silicate doped with erbium nitrate, thermally treated at 250 °C. Through systematic investigation, we explore the structural evolution and optical behavior of the thin films across varying Er3+ concentrations. The sol-gel demonstrated effective capabilities for substantial concentrations of Er3+ oxides through doping at lower calcination temperatures. The spectroscopic characteristics were studied using visible-near infrared spectroscopy (UV–vis–NIR), transmission electron microscopy, and Fourier transform infrared spectroscopy. Increasing the Er ratio decreased both the transmission and the energy band gap (3.6–3.34 eV) of the films while the absorption peak increased. The obtained results suggest that Er3+ activators demonstrate advantageous optical properties in the evaluated sodium silicate glass matrix. With the introduction of Er, optical transmittance ranges from 85 to 55% in the visible and near-infrared (NIR) regions, highlighting their advantageous characteristics. This research contributes to advancing the understanding of erbium-doped thin films for potential applications in optoelectronic devices and photonics.

Accurate and Transferable Machine Learning Potential for Molecular Dynamics Simulation of Sodium Silicate Glasses.

An accurate and transferable machine learning (ML) potential for the simulation of binary sodium silicate glasses over a wide range of compositions (from 0 to 50% Na2O) was developed. The potential energy surface is approximated by the sum of atomic energy contributions mapped by a neural network algorithm from the local geometry comprising information on atomic distances and angles with neighboring atoms using the DeePMD code [Wang, H. Comput. Phys. Commun. 2018, 228, 178-184]. Our model was trained on a large data set of total energies and atomic forces computed at the density functional theory level on structures extracted from classical molecular dynamics (MD) simulations performed at several temperatures from 300 to 3000 K. This allows for the generation of a robust and transferable ML potential applicable over the full compositional range of glass formability at different temperatures that outperforms the empirical potentials available in the literature in reproducing structures and properties such as bond angle distribution, total distribution functions, and vibrational density of state. The generality of the approach enables the future training of a potential with other or more elements allowing for simulations of structures, properties, and behavior of ternary and multicomponent oxide glasses with nearly ab initio accuracy at a fraction of the computational cost.

Composition formulas of silicate glasses

AbstractWe here extend the cluster‐plus‐glue‐atom model, originally developed for metallic glasses, to the interpretation of silicate glass compositions. By referring to β‐SiO2 crystal structure and to the widely recognized random network model, our model identifies a 16‐basic‐unit (or 32‐cation) composition formula {M1+2O}n–{M3+2O3}16−(m+n)–{M4+2O4}m, where monovalent unit {M1+2O} and quadrivalent unit {M4+2O4} cannot coexist and the trivalent units {M3+2O3} are constructed from pure trivalent cations such as {(Al,B)2O3} and from combinations of monovalent and divalent cations with the base quadrivalent Si such as {(Na,K)2/3Si4/3O3} and {(Mg,Ca)SiO3}. After analyzing some glasses of historical importance, it is pointed out that most of soda–lime–silica and aluminosilicate glasses satisfy closely {M3+2O3}16, as exemplified by ancient glasses as well as by modern ones, such as Container glass, 1980, Jena Standard Glass, and Corning Gorilla glasses of the first generation. On the other hand, borosilicate glasses feature extra {Si2O4} units ranging from 4 to 9.5 in their 16‐unit formulas, as exemplified by Corning E‐glass and Schott thermometer glass with {Si2O4}4 and Corning Pyrex with {Si2O4}9.5 containing the highest silica proportion. The number of monovalent cations in 32‐cation formulas follows linear dependences on the average cation valence e/c and on the 16‐unit parameters 2 m − 4n, showing that, except alkali‐free glasses, the compositions of soda–silicate glasses converge to 2N2 + N3 ≈ 8, where N2 and N3 are, respectively, the numbers of divalent and trivalent cations in the 32‐cation formula. The revelation of the composition rule shows the capacity of the cluster‐plus‐glue‐atom model in understanding the compositions of complex glassy systems.

First-principles NMR of oxide glasses boosted by machine learning.

Solid-state NMR has established itself as a cutting-edge spectroscopy for elucidating the structure of oxide glasses thanks to several decades of methodological and instrumental progress. First-principles calculations of NMR properties combined with molecular-dynamics (MD) simulations provides a powerful complementary approach for the interpretation of NMR data, although they still suffer from limitations in terms of size, time and high consumption of computational resources. We address this challenge by developing a machine-learning framework to boost predictive modelling of NMR spectra. We use kernel ridge regression techniques (least-squares support vector regression and linear ridge regression) combined with smooth overlap of atomic position (SOAP) atom-centered descriptors to efficiently predict NMR interactions: the isotropic magnetic shielding and the electric field gradient (EFG) tensor. As illustrated in this work, this approach enables the simulation of magic-angle spinning (MAS) and multiple-quantum magic-angle spinning (MQMAS) NMR spectra of very large models (more than 10 000 atoms) and an efficient averaging of NMR properties over MD trajectories of nanoseconds for incorporating finite-temperature effects, at the computational cost of classical MD simulations. We illustrate these advances for sodium silicate glasses (SiO2-Na2O). NMR parameters (isotropic chemical shift and electric field gradient) could be predicted with an accuracy of 1 to 2% in terms of the total span of the NMR parameter values. To include vibrational effects, an approach is proposed of scaling the EFG tensor in NMR simulations with a factor obtained from the time auto-correlation functions computed on MD trajectories.

Gamma Shielding and Dosimetry Parameters of Sodium-Silicate Glasses with Significant Role of TbF3 Addition

Gamma Shielding and Dosimetry Parameters of Sodium-Silicate Glasses with Significant Role of TbF3 Addition

Analysis of the Structure and Durability of Refractory Castables Impregnated with Sodium Silicate Glass

This study examines the impact of the impregnation of fireclay-based conventional (CC) and medium-cement castables (MCCs) with liquid sodium silicate glass under vacuum conditions. The goal is to assess how this treatment affects the physical and mechanical properties and durability (alkali and thermal shock resistance) of these castables used in biomass combustion boilers, where they are exposed to temperatures up to 1100 °C. The research work employs standard test methods to evaluate the physical and mechanical properties. Additionally, advanced techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and specific tests for alkali resistance and thermal shock resistance are used. The research findings suggest that impregnation with sodium silicate glass under vacuum significantly enhances the alkali resistance of both CC and MCCs. This improvement is primarily due to the reduction in porosity and the increase in density. SEM images reveal that the impregnated samples are coated with a glassy layer and the pores are partially filled with sodium silicate. Tests for alkali resistance demonstrate the formation of a protective glassy layer (with a thickness of 0.9–1.5 mm) on the castable surfaces, thereby reducing the further penetration of alkali into deeper layers of the samples. However, it is important to mention that the impregnated refractory castables have reduced resistance to thermal shock cycles.

Improvement in Long Term Bonding and Mechanical Performance by Using Glass Concrete in Combination with Xanthan Gum Exposed to Harsh Environment

Abstract Concrete is the mostly used construction material composed of a mixture of cement, water, aggregates (such as sand, gravel, or crushed stone), and often additional additives or admixtures. It is widely used in the construction industry for various applications due to its strength, durability, and versatility. Key characteristics of concrete include strength, durability, versatility, fire resistant, cost effective, weather resistant, insulation and decorative options. Concrete plays a vital role in the construction industry, providing the foundation for most buildings, infrastructure, and many other structures worldwide. Its composition and properties can be tailored to meet specific project requirements, making it an indispensable material in modern construction. Various fibers can be used to enhance the mechanical and bonding properties of concrete. Also waste fibers after recycling can be reduced the environmental burden. Keeping in this view, glass powder sodium silicate glass (SSG) is used as replacement of cement with different percentages 0%,4%,8%, and 12% in combination of xanthan gum 0.2% for all mixes. An experimental study is conducted to investigate the mechanical and durability properties of concrete by performing compression test, flexural test, alkali silica reactivity test, sulfate resistivity test and drying shrinkage test. For this, forty-eight concrete cylinders are prepared for compression test, forty-eight concrete prisms for flexural test and thirty-six mortar bars of four mixes are prepared for durability testing. Workability is checked of fresh concrete during the pouring of concrete cylinders. Poured cylinders’ samples are left for 7, 14, 21 and 28 days of curing. Different tests are performed on hardened concrete and mortar samples to evaluate the mechanical and durability properties. Results concluded that workability of four mixes lies between 60-80mm and compressive strength of concrete has been improved using glass powder (SSG). Optimum results have been achieved at 12% as compared to other mixes 4% and 8% of concrete samples. Fibrous material is used as a binding agent and fibrous concrete is suitable for humid environment where high strength and voids less concrete are required. Quantity of cement can be reduced by using different fibers as a replacement of cement. Research recommended that recycled glass powder can be used in concrete as construction material and 12% replacement is suitable for optimum results.

Study of sodium diffusion in silicate glasses. Molecular dynamics simulation

Molecular dynamics simulation is carried out to study diffusion in sodium silicate glasses (NS1, NS2, NS3, NS4) at temperatures of 973, 1173 and 1373 K. The result shows that the structure consists of network region where more than 83% of total Si and O are present, and Na-polyhedron region in which most Na-polyhedrons possess several non-bridging oxygens. The Na-polyhedron region changes slightly with temperature, and significantly with SiO2 concentration. During 150 ps the Si and O atoms vibrate around fixed points, while Na atoms move from one Na-polyhedron to another. The network region is static, while the Na-polyhedron region is seen dynamically. The glasses exhibit the dynamics heterogeneity. The simulation shows that Na atoms reside in a small part of Na-polyhedron region and move frequently through pathways consisting of polyhedrons with high local sodium density. Moreover, they move between polyhedrons often by small displacements and rarely by large jumps. We establish the expression for diffusion constant D Na via average resident time in polyhedron t RP and mean square displacement of Na per polyhedron δ. The dependence of D Na on δ and lnD Na on t RP is found to be linear.

Commentary on 'Combined experiments and atomistic simulations for understanding the effect of ZnO on the sodium silicate and sodium borosilicate glass network'

Recently, Sahu et al. [Combined experiments and atomistic simulations for understanding the effect of ZnO on the sodium silicate and sodium borosilicate glass network, J. of Non-Cryst. Solids 618 (2023) 122,550] published results from a combined experiment and simulation investigation that describes the effect of ZnO on sodium silicate and sodium borosilicate glass networks. Whilst the majority of the investigation remains sound, their conclusions relating to the chemical durability of silicate and borosilicate glasses containing ZnO are in need of clarification. This commentary addresses their conclusions and aligns them alongside the state-of-the-art understanding of the effect of Zn on the chemical durability, where the well-known positive effect of Zn on short-term glass dissolution becomes adverse over the long-term. This is caveated to consider the quantity of ZnO in the glass and on the specific dissolution test conditions.

Diffusion behaviors of sodium atoms within Si–O network in sodium silicate glasses: insights from molecular dynamics simulations

Diffusion behaviors of sodium atoms within Si–O network in sodium silicate glasses: insights from molecular dynamics simulations

Combined experiments and atomistic simulations for understanding the effect of ZnO on the sodium silicate and sodium borosilicate glass network

Combined experiments and molecular dynamics (MD) simulations were performed over wide range of glass compositions to understand the improved durability of borosilicate glass with ZnO addition. A significant change in glass structure was monitored from short range and intermediate range order parameters. The MD results were found to be in good agreement with the experimental data for Young's Modulus, glass transition temperature, and leaching. Both experiments and MD simulations report the enhanced chemical durability of glass with ZnO addition. Low R (Na2O/B2O3) and high K (SiO2/B2O3) of ZnO doped sodium borosilicate (Zn–NBS) glass surface compared to bare NBS represents the more stable structure of glass surface for Zn–NBS than NBS. The enhanced chemical resistivity of Zn–NBS was established from the increasing activation energy for diffusion of Na ions. The combined experiments and MD simulations disclose many interesting microstructure and dynamics due to the presence of ZnO in the glass.

Exploring the dielectric polarization and ionic conduction mechanisms in sodium-containing silicate and borosilicate glasses

The dielectric and electrical behavior of a sodium silicate glass (soda-lime-silica; SLS) and a sodium borosilicate glass (D263T) are systematically and comprehensively characterized by a combination of ac and dc techniques at various temperatures and electric fields. This study reveals that Na+ migration primarily influences the dielectric loss, energy efficiency, and leakage current in these glasses, with a less detrimental effect in D263T due to its higher activation energy for ionic conduction. Moreover, this study identifies an additional relaxation mechanism contributing to the leakage current in D263T which was not observed in SLS. The origin of this mechanism has not been extensively explored, and it is believed to arise from a more limited migration of Na+ ions associated with the short migration and accumulation of a second and less mobile ion near the anode.

Surface properties of alkali silicate glasses: Influence of the modifiers.

Using large-scale molecular dynamics simulations, we investigate the surface properties of lithium, sodium, and potassium silicate glasses containing 25 mol % of alkali oxide. The comparison of two types of surfaces, a melt-formed surface (MS) and a fracture surface (FS), demonstrates that the influence of the alkali modifier on the surface properties depends strongly on the nature of the surface. The FS exhibits a monotonic increase of modifier concentration with increasing alkali size while the MS shows a saturation of alkali concentration when going from Na to K glasses, indicating the presence of competing mechanisms that influence the properties of a MS. For the FS, we find that larger alkali ions reduce the concentration of under-coordinated Si atoms and increase the fraction of two-membered rings, implying an enhanced chemical reactivity of the surface. For both types of surfaces, the roughness is found to increase with alkali size, with the effect being more pronounced for the FS than for the MS. The height-height correlation functions of the surfaces show a scaling behavior that is independent of the alkali species considered: The ones for the MS are compatible with the prediction of the frozen capillary wave theory while the ones for the FS show a logarithmic growth, i.e., on the nanoscale these surfaces are not self-affine fractals. The influence of the modifier on the surface properties are rationalized in terms of the interplay between multiple factors involving the size of the ions, bond strength, and charge balance on the surface.

Nanoindentation‐induced evolution of atomic‐level properties in silicate glass: Insights from molecular dynamics simulations

AbstractIndentation has been widely used for investigating the mechanical behavior of glasses. However, how the various microscopic properties (such as atomic structure and mechanics) of glass evolve from the immediate contact with the indenter to the far‐field regions, and how these observables are correlated to each other remain largely unknown. Here, using large‐scale molecular dynamics simulations, we investigate the response of a prototypical sodium silicate glass under shape contact load up to an indentation depth of 25 nm. Both the short‐ and intermediate‐range structures are found to exhibit notable changes below the indent, indicating that indentation deformation induces a more disordered and heterogeneous network structure. In addition, we find that the indentation‐induced changes of local properties all exhibit an exponential decaying behavior with increasing distance from the indent. Comparison of the characteristic decay lengths of these local properties indicates that the structural origins of shear flow and densification are the changes of the network modifier's coordination environment and the inter‐tetrahedral connection, respectively. The decay of densification is considerably slower than that of shear strain, implying that the former might contribute more to the deformation at the far‐field regions. Our findings not only contribute to an atomistic understanding of the indentation response of silicate glasses but also pave the way toward rational design of damage‐resistant glassy materials.