Silica Nanocomposites Research Articles

Bionic Micro-Texture Duplication and RE3+ Space-Selective Doping of Unclonable Silica Nanocomposites for Multilevel Encryption and Intelligent Authentication.

High-capacity optical data storage and information encryption by using glass substrates are fascinating due to merits of expanding the functionality and applicability of the optoelectronic field. However, the development of glass substrate-based multi-dimensional information encryption methods has remained a challenge because of the high hardness, brittleness and melting temperature of glasses. Herein, inspired by the unique natural structure of plant leaves, multicolor micro-texture-based physical unclonable functions (PUFs) fluorescence glass labels (MTPLs) are exploited by using ultraviolet photocurable silica nanocomposites and soft replication method. It is the first time that simultaneous rare-earth ion (RE3+ ) space-selective doping and bionic micro-texture replication onto transparent glass have been realized, in which the doping position and fluorescence color of RE3+ and height information of unclonable micro-texture can be selectively equipped for multilevel information encryption. The prepared micro-scale MTPLs are endowed with tunable multilevel authentication models, including macro-scale multicolor fluorescent 2D patterns, micro-scale pattern, color 3D information and intelligence authentication. A high-performance anti-counterfeiting platform with interactive authentication is also established based on the high robustness and security of MTPLs. Such unclonable bionic MTPLs based on RE3+ space-selective doping and micro-texture duplication provide an effective and potentially universal approach for multilevel encryption and intelligent authentication.

The effect of chitosan on the physico-mechanical and antimicrobial properties of gamma irradiated ethylene propylene diene monomer/fumed silica nanocomposites

The effect of chitosan on the physico-mechanical and antimicrobial properties of gamma irradiated ethylene propylene diene monomer/fumed silica nanocomposites

Elongational flow mixing: A novel innovative approach to elaborate high-performance SBR-based elastomer compounds

Abstract A dominant extensional flow mixing device (Reactor/Elongational Flow MiXer; RMX) was used to prepare styrene-butadiene rubber (SBR)/silica nanocomposites with high physical performances. First, the processing parameters such as the temperature, number of mixing cycles, and sequenced mixing protocol have been optimized. Thereafter, the morphological structure of different compounds was probed using scanning and transmission electron microscopy. The prediction of the flow properties during processing of uncured materials were modeled using the dynamic and capillary rheometry. The thermo-mechanical sweep behavior of the as-prepared silica-filled SBR specimens was also investigated. By comparing with SBR/silica compounds prepared by the internal mixer, it was proven that elongational flow mixing process can not only reduce mixing energy consumption but also make the manufactured parts to have high state of dispersion, excellent viscoelastic properties, high extensional and yield stresses, and high elastic and rubbery moduli. This study highlights the potential of the elongational flow mixing as an innovative processing approach which is compatible with the industrial expectations for the fast manufacturing of high-performance silica and carbon black filled rubber compounds.

Surface enhanced Raman scattering investigation of tecovirimat on silver, gold and platinum loaded silica nanocomposites: Theoretical analysis (DFT) and molecular modeling

As of today, there have been 612 million confirmed cases of coronavirus disease (COVID-19) around the world, with over 6 million fatalities. Tecovirimat (TPOXX) is an anti-viral drug, and it was the first drug approved for the treatment of anti-pox virus in the US. However, the effectiveness of this drug against COVID-19 has not yet been explored. Since TPOXX is an anti-viral drug, an attempt has been made to determine its ability to act as a COVID inhibitor. Recent medical advances have resulted in the development of nano cage-based drug delivery. Drug delivery clusters based on nano cages have recently been used in the medical industry. As such, we used DFT coupled to the B3LYP/LANL2DZ basis set to study the adsorption behavior of the anti-viral drug TPOXX on Au/Ag/Pt⋯SiO2loaded silica nanocomposites. In order to identify the active site of the molecule, we have used the frontier molecular orbital (FMO) theory of molecular electrostatic potential (MEP). The compound and its complexes obey Lipinski's rule of five and have good drug-likeness properties based on the bioactivity evaluation. The biological properties of organic molecules and nano metal clusters were compared. The TPOXX with its nanocomposites was also studied in terms of Electron Localization Function (ELF) and Localized Orbital Locator (LOL). Molecular docking was performed for both pure molecule and its silica nanocomposites-doped derivatives with the chosen proteins to discuss the protein-ligand binding properties. These results could be more helpful in designing the drug and exploring its application for the inhibition of SARS-CoV-2.

Enhanced Photocatalytic Degradation of Tetracycline-Class Pollutants in Water Using a Dendritic Mesoporous Silica Nanocomposite Modified with UiO-66

Enhanced Photocatalytic Degradation of Tetracycline-Class Pollutants in Water Using a Dendritic Mesoporous Silica Nanocomposite Modified with UiO-66

Electrochemically pre-lithiated SiO2@C nanocomposite anodes for improved performance in lithium-ion batteries

Silica (SiO2)-based materials are a promising alternative anode material due to their high specific capacity, abundance, safety, and environmental friendliness. However, the significant volume expansion and the formation of a solid electrolyte interphase (SEI) with electrolytes cause active lithium loss and result in poor Coulombic efficiency of SiO2-based materials, which hinder their commercial applications. Therefore, pre-lithiation, a method of embedding extra lithium ions in the electrodes prior to cycling, is an effective approach to replenish the largely irreversible lithium loss during cycling and overcomes these challenges. In this study, carbon-coated silica (SiO2@C) nano composite was synthesized via a sol–gel method and the beneficial impacts of using pre-lithiated SiO2@C electrodes in coin cells were investigated. It is shown that the carbon coating onto the surface of the SiO2 particles and the pre-lithiation method led to a distinct improvement in the overall capacity and Coulombic efficiency of the cells due to the pre-formed SEI and the presence of a lithium reservoir within the anode. Furthermore, the anodes exhibited excellent cycling stability and good rate capability up to 2 A g−1.

Structural, optical, electrical and magnetic properties of lithium zinc ferrite – Silica nanocomposites

Lithium zinc ferrite - silica nanocomposites; with a formula [Li0.5−x/2ZnxFe2.5−x/2O4]30%[SiO2]70%, have been synthesized using ultrasonic assisted sol-gel auto combustion method. Thrust of the study is to investigate effect of zinc substitution in lithium ferrite (dispersed in silica matrix) on structural, optical, electrical and magnetic properties. X-ray diffraction (XRD), UV Visible (UV-Vis), Transmission Electron Microscopy (TEM), Complex Impedance Spectroscopy (CIS) and Vibrating Sample Magnetometry (VSM) have been employed to investigate the samples. XRD patterns confirm the phase purity and revealed that incorporation of Zn2+ at Li+ sites expand the unit cell dimensions from 8.3281 Å to 8.4398 Å, strain and crystallite size escalates from 0.29 to 1.42 and 18.28–27.50 nm respectively. Results from TEM and XRD match well indicating least agglomeration. Optical bandgap and refractive index show a significant effect on increasing zinc content. The impedance (Z) is found to reduce with increase in Zn2+ and may be attributed to enhancement in crystal boundaries. Dielectric properties were explored using cole-cole theoretical fitting of permittivity (ε), universal dielectric response (UDR) model, Koop’s theory and Maxwell–Wagner (M-W) mechanism. Complex electrical modulus (M*) formulation has been employed to explore the transport mechanism. Cole-cole plots in M* reveal that all the samples, except x = 0.50, show relaxation originating from grain boundaries whereas x = 0.50 sample shows contributions from both, grain and grain boundaries. Equivalent circuits have been derived using M* spectrum and are presented with circuit parameters. Frequency dependent AC conductivity (σac) curves have been fitted successfully using Jonscher’s power law; σac for a typical sample x = 0.50 was fitted using double power law. All samples have η ≤ 1, confirming correlated barrier hopping (CBH) mechanism of conductivity. Present system exhibits lower dc conductivity due to highly resistive silica in the samples. Magnetic properties have been studied using Vibrating Sample Magnetometry (VSM). Zn2+ substitution has a significant impact on magnetization due to migration of cations.

Adsorption behavior, different green solvent effect and surface enhanced Raman spectra (SERS) investigation on inhibition of SARS-CoV-2 by antineoplastic drug Carmofur with silver/gold/platinum loaded silica nanocomposites: A combined computational analysis and molecular modelling approach

In recent times, extensive research has been carried out to uncover effective drug treatments for coronavirus disease (COVID-19). The Carmofur (HCFU) molecule is primarily known for its antineoplastic properties and its use in cancer treatment. Nowadays, the antineoplastic drug Carmofur has shown its effectiveness in inhibiting the SARS-CoV-2 virus. The primary objective of this article is to utilize theoretical knowledge to explore the absorption mechanism and interaction between the HCFU molecule and the noble metal (Ag/Au/Pt)-loaded silica nanocomposites (HCFU + Ag/Au/Pt…SiO2). The optimized geometry, frequency, and intensity of the vibrational bands of the HCFU molecule and its complexes were obtained from the DFT method with the LANL2DZ basis set. The SERS technique was carried out to explore the adsorption of HCFU molecule with metal (Ag/Au/Pt)-loaded silica nanocomposites. The chemical reactivity and the charge distribution within the molecule were analysed with the help of HOMO-LUMO, Molecular Electrostatic Potential (MEP), Electron Localized Function (ELF), and Localized Orbital Locator (LOL) studies. The polar protic (ethanol, methanol, and water) and polar aprotic (DMSO) solvents were used to analyse the UV–Visible spectra of the molecules using the TD-DFT method. The drug-likeness properties of the molecules were calculated utilizing Lipinski’s rule, and finally, the molecular docking prediction was carried out for the Carmofur (HCFU) and its complexes with the selected proteins.

Three dimensional scaffolds of hybrid PLA/PCL/HA/silica nanocomposites for bone tissue engineering

Three dimensional scaffolds of hybrid PLA/PCL/HA/silica nanocomposites for bone tissue engineering

Natural Rubber/Hexagonal Mesoporous Silica Nanocomposites as Efficient Adsorbents for the Selective Adsorption of (-)-Epigallocatechin Gallate and Caffeine from Green Tea.

(-)-Epigallocatechin gallate (EGCG) is a bioactive component of green tea that provides many health benefits. However, excessive intake of green tea may cause adverse effects of caffeine (CAF) since green tea (30-50 mg) has half the CAF content of coffee (80-100 mg). In this work, for enhancing the health benefits of green tea, natural rubber/hexagonal mesoporous silica (NR/HMS) nanocomposites with tunable textural properties were synthesized using different amine template sizes and applied as selective adsorbents to separate EGCG and CAF from green tea. The resulting adsorbents exhibited a wormhole-like silica framework, high specific surface area (528-578 m2 g-1), large pore volume (0.76-1.45 cm3 g-1), and hydrophobicity. The NR/HMS materials adsorbed EGCG more than CAF; the selectivity coefficient of EGCG adsorption was 3.6 times that of CAF adsorption. The EGCG adsorption capacity of the NR/HMS series was correlated with their pore size and surface hydrophobicity. Adsorption behavior was well described by a pseudo-second-order kinetic model, indicating that adsorption involved H-bonding interactions between the silanol groups of the mesoporous silica surfaces and the hydroxyl groups of EGCG and the carbonyl group of CAF. As for desorption, EGCG was more easily removed than CAF from the NR/HMS surface using an aqueous solution of ethanol. Moreover, the NR/HMS materials could be reused for EGCG adsorption at least three times. The results suggest the potential use of NR/HMS nanocomposites as selective adsorbents for the enrichment of EGCG in green tea. In addition, it could be applied as an adsorbent in the filter to reduce the CAF content in green tea by up to 81.92%.

Evaluation and correlation of self-healing functionalized silane-based hybrid nanocomposite materials as corrosion inhibitor

Benzimidazole is a widely used compound exhibits intriguing networking capabilities. In this study, we synthesized and characterized mesoporous silica nanocomposites loaded with benzimidazole on reduced graphene oxide (GOSB). We investigated the impact of these composites on the long-term corrosion rate control of steel surfaces in aqueous solutions. The novel material's formation and behavior in the aqueous solution were assessed through comprehensive multi-technique analyses. The corrosion inhibition efficiency of GOSB was found to be remarkably high, with values of 98.07% and 99.29% determined from electrochemical impedance spectroscopy and potentiodynamic polarization studies, respectively. The superior protection observed on the steel surface in the aqueous GOSB solution can be attributed to the synergistic effects of two distinct surface layers and solution-based mechanisms. The interaction between the d-π* orbitals of the steel surface and benzimidazole molecules within GOSB emerges as the primary contributor to the formation of the protective layer. This straightforward solution-based approach opens up new avenues for future research in the realm of industrial corrosion prevention and coating.

In vitro and Bioimaging Studies of Mesoporous Silica Nanocomposites Encapsulated Iron-oxide and Loaded Doxorubicin Drug (DOX/IO@Silica) as Magnetically Guided Drug Delivery System.

In recent years, the delivery of drugs by nanocomposites has emerged as an exciting field of research for bio-imaging tools and targeted cancer treatment. The large surface area and porous volume of mesoporous silica nanocomposites (MSN's) have gained a lot of interest for their application in the delivery of drugs and the magnetic properties of iron oxide (IO) nanocomposites play a key role in the targeted delivery system. In this study, mesoporous silica encapsulated IO nanocomposites loaded with doxorubicin (DOX) were synthesized for the magnetically guided delivery of anticancer drugs. The synthesis of IO nanocomposites was done through the precipitation method, and then silica encapsulation and drug loading were done by the StÖber method. The magnetically driven delivery of the drug is produced by the encapsulation of magnetically active IO in the mesoporous silica shell. The controlled release of DOX is possible because of the MSN's. TEM images show that the nanocomposites have a spherical morphology and average diameter in the range of 120 nm. Power-XRD data confirm the crystalline nature of nanocomposites. The strong absorption peak was observed in UV-Visible spectroscopy at 490 nm and quenching in fluorescence spectra confirms the encapsulation of DOX in the mesoporous silica shell. VSM data showed the magnetic nature of nanocomposites, with large magnetic susceptibility (74.88 emu/g). The use of DOX/IO@Silica nanocomposites as a sustainable drug release and targeted drug delivery vehicle has been reported here. The pH dependent release of DOX was studied and significant release was observed at lower pH. In-vitro cell viability assay and fluorescence imaging assay have demonstrated that these nanocomposites show significant dose-dependent toxicity to cancer cells in the presence of a magnetic field. In-vitro studies via the MTT assay showed that these synthesized nanocomposites in culture are non-toxic to healthy cells compared to DOX-induced cytotoxicity due its controlled release and can be further strengthened by magnetic guidance. Therefore, due to its optical properties and potential for guided delivery of drug to the targeted site, these nanocomposites are ideal as an anticancer agent and bio-imaging prob.

Improving the properties of gap-filling materials for pottery artifacts with nano silica and nano kaolinite polymeric nanocomposites

Purpose The study aims to assess the efficiency of nanocomposite to improve the properties of gap-filling materials for pottery artifacts. Design/methodology/approach Five different pastes were used in the laboratory studies. The pastes consist mainly of pottery powder (grog), dental plaster, microballoons and an adhesive of Primal AC33, nano-silica and nano kaolinite in various concentrations. The prepared samples were subjected to accelerated heat and light aging. Besides, some investigations were used to evaluate the efficacy of the additive nanomaterials, such as TEM, digital and scanning electron microscopy microscopes. Contact angle, color change, shrinkage degree, physical properties and compressive strength tests were also conducted. Findings The results indicated that using Nano-silica considerably improves the mechanical strength and decreases the shrinkage of gap-filling materials. According to the results, a mixture of grog, microballoons and Primal AC33/Nano-silica Nanocomposites is the optimal gap-filling paste for archaeological pottery. Moreover, this paste showed a higher contact angle (120°), lower color change (ΔE = 2.62), lower shrinkage (3.3%), lower water absorption (3.36%), lower porosity (5.05%) and higher compressive strength (5124 N/mm2). Originality/value This paper attains to develop an economic polymer-nanocomposite that can be used with gap-filling materials for pottery artifacts.

A novel strategy to functionalize styrene butadiene rubber toward enhanced interfacial interaction with silica

AbstractIncorporation of nanofillers (such as silica) into elastomer matrix is the most common strategy to prepare high‐performance rubber products. However, the poor dispersion of nanofillers in non‐affinity rubber materials and the weak interfacial interaction significantly limit the processing and mechanical properties. To reduce the polarity difference and enhance the interfacial interaction between silica and styrene butadiene rubber (SBR), we prepared a hydroxyethyl acrylate‐grafted SBR (SBR‐g‐HEA) through the redox initiator system, and subsequently fabricated SBR‐g‐HEA/silica nanocomposites by simple mechanical blending. The effects of reaction conditions on the grafting rate were studied in detail. ATR‐FTIR and 1H‐NMR collectively confirmed the successful grafting of HEA groups on SBR molecular chains, and the grafting fraction could be regulated from 0% to 2.5%. Scanning electron microscope (SEM) and rubber processing analyzer (RPA) showed that the incorporation of HEA could significantly improve the dispersion of silica nanoparticles in SBR matrix. Notably, the resulting SBR‐g‐HEA exhibited significantly enhanced attributes when compared to their unmodified counterparts, including superior mechanical properties, improved wear resistance, and reduced heat generation. The strategy proposed here provided insights toward the fabrication of non‐affinity rubber/filler nanocomposites for high‐performance rubber products and green tire.

Niobium pentoxide / silica nanocomposites with hierarchical pore structure as methylene blue and doxycycline adsorbent

Nanocomposites formed by niobium pentoxide dispersed in a silica matrix, with pores modulated by the addition of a soluble polymer (polyethylene glycol 10000), were calcined at different temperatures and applied to remove methylene blue (MB) and doxycycline (DOX) from water. The temperature of calcination changed the morphology of the niobium pentoxide nanoparticles inserted in the silica matrix and the textural characteristics of the nanocomposites, influencing their adsorption properties. The adsorption of the two contaminants used as models was sensitive to the pH variation of the solution, being optimal at pH 11 and 9 for the removal of MB and DOX, respectively. The effect of ionic strength corroborated by the zeta potential and FTIR analyses of the nanocomposite, before and after adsorption, showed that the adsorption of MB (exothermic process) is due only to electrostatic interaction, while the adsorption of DOX (endothermic process) is due to electrostatic and n-π interactions. Both removal processes were spontaneous. The use of the nanocomposites for the adsorption of the two contaminants is efficient and economical since they can be regenerated and reused.

Characterization of new modified mesostructured silica nanocomposites fabricated for effective removal of aromatic acids

Santa Barbara Amorphous-15 (SBA-15) is a mesoporous molecular sieve with a large surface area and is extensively applied in purification, separation, and catalytic procedures. In this study, an SBA-15 was prepared from a sodium silicate precursor, and pentaethylene hexamine was anchored to its surface. A composite named N-SBA-15 was characterized using several experimental techniques. FTIR and XPS measurements confirmed that amino groups were conjugated on the surface of SBA-15. XRD and TEM confirmed that N-SBA-15 comprised highly ordered, hexagonal mesopore structures, which were not destroyed by the addition of amino groups. After functionalization, the surface area, pore volume, and pore size of the composite were 188 m2/g, 0.303 cm3/g, and 5.0 nm, respectively. N-SBA-15 was applied in the adsorption of aromatic acids, namely tannic acid (TA), acid red 1 (AR-1), and acid blue 40 (AB-40). The influence of various adsorption conditions such as dye concentration, adsorbent dosage, solution pH, and solution temperature was investigated. For AB-40 dye, the N-SBA-15 composite exhibited 40 times higher adsorption capacity than pure SBA-15. The highest adsorption capacities of N-SBA-15 for TA, AB-40, and AR-1 were 869, 818, and 308 mg/g, respectively. Thermodynamic studies were conducted to evaluate the exothermic property of the adsorption process and spontaneous behavior. The adsorptive data fitted well with pseudo-second-order and Langmuir isotherm models. Results confirmed that amino-modified SBA-15 material is a promising adsorbent for the elimination of aromatic acids form aqueous solution.

Heterogeneous Glass Transition Behavior of Poly(Ethylene oxide)/Silica Nanocomposites via Atomistic MD Simulations

Heterogeneous Glass Transition Behavior of Poly(Ethylene oxide)/Silica Nanocomposites via Atomistic MD Simulations

酸処理によるケイ酸カルシウムからのナノコンポジット合成とCO<sub>2</sub>固定化特性の評価

Xonotlite, with a chemical formula of Ca6(Si6O17)(OH)2, has been widely used as a thermal insulation material due to its high porosity and chemical/physical stabilities. As a potential recycle use of Xonotlite, CO2 fixation is promising when considering its high alkali content and macroporous structure. In this study, Xonotlite was chemically activated to form nanocomposites of silica and calcium salt by optimizing an acid treatment. It was found that Xonotlite treated with acetic acid at 1.0 mol/L keeps the original macroporous structure of Xonotlite, and simultaneously segregates calcium salt on the surface of the residual silica. The nanocomposite of silica and calcium salt exhibits the capability of CO2 fixation and high cycle stability thanks to the unique structural feature of the composite.

CoFe2O4 decorated graphene/C18-functionalized mesoporous silica nanocomposites prepared for magnetic enrichment and electrochemical detection of promethazine in beef

Promethazine (PHZ) is used as a sedative in veterinary medicine, and its residue can threaten the health of human. The electrochemical detection of PHZ is suitable method for application in the field. However, the traditional electroanalysis is difficult to perform directly in meat samples due to matrix interference. This work integrates magnetic solid-phase extraction and differential pulse voltammetry for highly sensitive and selective determination of PHZ in beef and beef liver for the first time. CoFe2O4/graphene coated with C18-functionalized mesoporous silica (MG@mSiO2-C18) is synthesized as dispersed magnetic adsorbent to extract PHZ. Magnetic glassy carbon electrode modified with nitrogen-doped hollow carbon microspheres (HCM) attracts the MG@mSiO2-C18 with PHZ, and directly detects the PHZ without elution procedure. MG@mSiO2-C18 can separate PHZ to avoid the interference of impurities on following detection, and also concentrate PHZ on magnetic electrode. Additionally, the electrode modification with HCM can amplify the electrochemical signal of PHZ. Finally, the integrated PHZ determination method exhibits a wide linear range from 0.08 µmol/L to 300 µmol/L with a low limit of detection of 9.8 nmol/L. The beef sample analysis presents excellent recovery, demonstrating that this protocol is promising for the rapid and onsite detection of PHZ in real meat samples

Geothermal drilling using reprocessable shape memory polymer nanocomposite

The use of efficient lost circulation materials (LCMs) is essential to reducing fluid loss in geothermal wells. The purpose of this work is to assess novel reprocessable smart shape memory polyurethane (SMPU) LCMs based on SMPU silica nanocomposite for geothermal drilling. Improving the recyclability of SMPU LCMs enhances resource utilization and minimizes drilling fluid waste. The novel isocyanate/amino-terminated surface of the modified silica nanoparticles (MSNPs) was chemically incorporated into the polyurethane during the synthesis of SMPU nanocomposite using an in-situ two-step polymerization method. The results show that the chemically integrated MSNPs effectively reinforce the SMPU matrix by improving the dispersion of the silica nanoparticles relative to unmodified silica-SMPU nanocomposites. After three cycles of the shape memory test, MSNPs-SMPU showed remarkable shape memory stability with a shape recovery ratio of over 80%. Fracture sealing at conditions encountered in geothermal drilling demonstrated 4% higher sealing pressure for MSNPs-SMPU LCMs coupled with 11% lower fluid loss, which increased drilling procedure safety and environmental protection. MSNPs-SMPU LCMs offer excellent reprocessability without affecting the fracture sealing capability. On the other hand, commercial Mica LCMs showed an 83% drop in fracture sealing pressure in their third cycle owing to particle crushing.