Silica-based Nanocomposites Research Articles

Recent advances of mesoporous silica-based nanocomposites for photodynamic therapy: A review

Recent advances of mesoporous silica-based nanocomposites for photodynamic therapy: A review

High-Resolution Structuring of Silica-Based Nanocomposites for the Fabrication of Transparent Multicomponent Glasses with Adjustable Properties.

Silicate-based multicomponent glasses are of high interest for technical applications due to their tailored properties, such as an adaptable refractive index or coefficient of thermal expansion. However, the production of complex structured parts is associated with high effort, since glass components are usually shaped from high-temperature melts with subsequent mechanical or chemical postprocessing. Here for the first time the fabrication of binary and ternary multicomponent glasses using doped nanocomposites based on silica nanoparticles and photocurable metal oxide precursors as part of the binder matrix is presented. The doped nanocomposites are structured in high resolution using UV-casting and additive manufacturing techniques, such as stereolithography and two-photon lithography. Subsequently, the composites are thermally converted into transparent glass. By incorporating titanium oxide, germanium oxide, or zirconium dioxide into the silicate glass network, multicomponent glasses are fabricated with an adjustable refractive index nD between 1.4584-1.4832 and an Abbe number V of 53.85-61.13. It is further demonstrated that by incorporating 7wt% titanium oxide, glasses with ultralow thermal expansion can be fabricated with so far unseen complexity. These novel materials enable for the first time high-precision lithographic structuring of multicomponent silica glasses with applications from optics and photonics, semiconductors as well as sensors.

Efficient removal of ibuprofen from aqueous solutions using silica-based nanocomposites: A comparative study

This study investigates the efficacy of environmentally friendly silica-based nanocomposites, SiO2-Fe3O4 and SiO2-ZnO, for removing Ibuprofen (IBU) from aqueous solutions. The synthesized nanocomposites were characterized using various techniques, such as SEM, TEM, EDS, and FTIR. The adsorption capabilities of IBU onto these nanocomposites were explored through comparative analysis, focusing on factors such as pH, initial pollutant concentration, contact time, and temperature. Results reveal that the adsorption process is pH-dependent, and the lower pH levels enhance the adsorption process. The IBU removal process is faster with SiO2-Fe3O4 compared to SiO2-ZnO. Kinetic modeling suggests a pseudo-second-order mechanism [Formula: see text] for IBU adsorption onto the surfaces of both adsorbents. Langmuir and Freundlich isotherms were employed and demonstrated to analyze the equilibrium data. The Langmuir model revealed a higher maximum adsorption capacity for SiO2-Fe3O4 [Formula: see text] than SiO2-ZnO [Formula: see text]. Thermodynamic analysis indicates a chemisorption mechanism for SiO2-ZnO and a physisorption mechanism for IBU molecules on the surface of SiO2-Fe3O4. In addition, the standard thermodynamic parameters for the adsorption process indicate that IBU adsorption via both nanocomposites is exothermic, resulting in reduced entropy, and occurs spontaneously. This research introduces silica-based nanocomposites with Fe3O4 nanoparticles for efficient Ibuprofen removal from aqueous solution. The magnetic properties allow easy separation and reusability, enhancing treatment effectiveness. The study offers valuable insights for improving water treatment strategies with potential industrial applications.

Closed-Loop Recyclable Silica-Based Nanocomposites with Multifunctional Properties and Versatile Processability.

Most plastics originate from limited petroleum reserves and cannot be effectively recycled at the end of their life cycle, making them a significant threat to the environment and human health. Closed-loop chemical recycling, by depolymerizing plastics into monomers that can be repolymerized, offers a promising solution for recycling otherwise wasted plastics. However, most current chemically recyclable polymers may only be prepared at the gram scale, and their depolymerization typically requires harsh conditions and high energy consumption. Herein, it reports less petroleum-dependent closed-loop recyclable silica-based nanocomposites that can be prepared on a large scale and have a fully reversible polymerization/depolymerization capability at room temperature, based on catalysis of free aminopropyl groups with the assistance of diethylamine or ethylenediamine. The nanocomposites show glass-like hardness yet plastic-like light weight and toughness, exhibiting the highest specific mechanical strength superior even to common materials such as poly(methyl methacrylate), glass, and ZrO2 ceramic, as well as demonstrating multifunctionality such as anti-fouling, low thermal conductivity, and flame retardancy. Meanwhile, these nanocomposites can be easily processed by various plastic-like scalable manufacturing methods, such as compression molding and 3D printing. These nanocomposites are expected to provide an alternative to petroleum-based plastics and contribute to a closed-loop materials economy.

Thermal-protective and oxygen-resistant nanocoating using silica-nanocomposites for laser thinning of polymorphic molybdenum ditellurides

Laser irradiation has been investigated as a method of fabricating atomically thin crystals from layered two-dimensional (2D) materials with precise thickness control. However, during laser irradiation, inevitable structural changes can occur in the 2D materials due to the high thermal energy, altering their physical and chemical properties and introducing disorder, which has hindered the study and use of the intrinsic properties of atomically thin materials. In this study, we report a laser thinning method using a new coating material, a layered silica-based nanocomposite (SNC), that preserves the pristine crystal structure of a polymorphic 2D material, MoTe2, down to an atomically thin geometry. We confirmed that the nano-porous coating of layered silica-based nanocomposite (SNC) behaved as a good thermal-protective and oxygen-resistant material during the laser thinning process using various experimental techniques, atomic force microscopy, Raman spectroscopy and scanning photoelectron microscopy with synchrotron radiation. Accordingly, our SNC coating of 2D materials is a promising way to engineer the phase and geometry of polymorphic 2D materials, enabling versatile applications in various optoelectronic, spintronic, and electronic devices.

Application of Microscopic Highly Hydrophilic Silica-Based Nanocomposites with High Surface Exposure in the Efficient Identification of Intact N-Glycopeptides.

Glycosylation of proteins regulates the life activities of organisms, while abnormalities of glycosylation sites and glycan structures occur in various serious diseases such as cancer. A separation and enrichment procedure is necessary to realize the analysis of the glycoproteins/peptides by mass spectrometry, for which the surface hydrophilicity of the material is an important factor for the separation and enrichment performance. In the present work, under the premise of an obvious increase of the surface silicon exposure (79.6%), the amount of surface polar silanol is remarkably generated accompanying the introduction of the active amino groups on the surface of silica. The microscopic hydrophilicity, which is determined with water physical-adsorption measurements and can directly reflect the interaction of water molecules and the intrinsic surface of the material, maximally increases by 44%. This microscopically highly hydrophilic material shows excellent enrichment ability for glycopeptides, such as extremely low detection limits (0.01 fmol μL-1), remarkable selectivity (1:8000), and size exclusion effects (1:8000). A total of 677 quantifiable intact N-glycopeptides were identified from the serum of patients with cervical cancer, and the glycosylation site and glycan structure were analyzed in depth, indicating that this novel material can show a broad practical application in cervical cancer diagnosis.

Developing Post-Consumer Recycled Flexible Polypropylene and Fumed Silica-Based Nanocomposites with Improved Processability and Thermal Stability.

Collection and mechanical recycling of post-consumer flexible polypropylene packaging is limited, principally due to polypropylene being very light-weight. Moreover, service life and thermal-mechanical reprocessing degrade PP and change its thermal and rheological properties according to the structure and provenance of recycled PP. This work determined the effect of incorporating two fumed nanosilica (NS) types on processability improvement of post-consumer recycled flexible polypropylene (PCPP) through ATR-FTIR, TGA, DSC, MFI and rheological analysis. Presence of trace polyethylene in the collected PCPP increased the thermal stability of the PP and was significantly maximized by NS addition. The onset decomposition temperature raised around 15 °C when 4 and 2 wt% of a non-treated and organically modified NS were used, respectively. NS acted as a nucleating agent and increased the crystallinity of the polymer, but the crystallization and melting temperatures were not affected. The processability of the nanocomposites was improved, observed as an increase in viscosity, storage and loss moduli with respect to the control PCPP, which were deteriorated due to chain scission during recycling. The highest recovery in viscosity and reduction in MFI were found for the hydrophilic NS due to a greater impact of hydrogen bond interactions between the silanol groups of this NS and the oxidized groups of the PCPP.

Role of silica-based porous cellulose nanocrystals in improving water absorption and mechanical properties

Epoxy resins are important thermosetting polymers. They are widely used in many applications i.e., adhesives, plastics, coatings and sealers. Epoxy molding compounds have attained dominance among common materials due to their excellent mechanical properties. The sol-gel simple method was applied to distinguish the impact on the colloidal time. The properties were obtained with silica-based fillers to enable their mechanical and thermal improvement. The work which we have done here on epoxy-based nanocomposites was successfully modified. The purpose of this research was to look into the effects of cellulose nanocrystals (CNCs) on various properties and applications. CNCs have recently attracted a lot of interest in a variety of industries due to their high aspect ratio, and low density which makes them perfect candidates. Adding different amounts of silica-based nanocomposites to the epoxy system. Analyzed with different techniques such as Fourier-transformed infrared spectroscope (FTIR), thermogravimetric analysis (TGA) and scanning electronic microscopic (SEM) to investigate the morphological properties of modified composites. The various %-age of silica composite was prepared in the epoxy system. The 20% of silica was shown greater enhancement and improvement. They show a better result than D-400 epoxy. Increasing the silica, the transparency of the films decreased, because clustering appears. This shows that the broad use of CNCs in environmental engineering applications is possible, particularly for surface modification, which was evaluated for qualities such as absorption and chemical resistant behavior.

A Novel Biocidal Nanocomposite: Spherical Silica with Silver Ions Anchored at the Surface.

This article is devoted to a novel class of antimicrobial agents: nanocomposites composed of spherical silica and silver ions located at the silica's surface with the assumed distribution. Such materials are in high demand due to the increasing threat from bacterial strains that are becoming resistant to currently known antibiotics. In particular, we focus on materials that make it possible to limit the growth of bacterial colonies on a variety of tactile surfaces. In this paper, we present a method for preparing a silica-based nanocomposite containing silver ions and the analysis of their antimicrobial properties. Our research revealed that the presence of tested nanocomposite induces very high oxidative stress in the bacteria cell, damaging and modifying bacterial DNA, creating oxidized guanines, cytosines, or adenines, which causes its very rapid destruction, leading to cell death.

Stabilization of the (C2H5)4NHSO4 High-Temperature Phase in New Silica-Based Nanocomposite Systems.

In this study, the electrotransport, thermal and structural properties of composite solid electrolytes based on (C2H5)4NHSO4 plastic phase and silica (1 - x)Et4NHSO4-xSiO2, where x = 0.3-0.9) were investigated for the first time. The composites were prepared by mechanical mixing of silica (300 m2/g, Rpore = 70Å) and salt with subsequent heating at temperatures near the Et4NHSO4 melting point. Heterogeneous doping is shown to change markedly the thermodynamic and structural parameters of the salt. It is important that, with an increase in the proportion of silica in the composites, the high-temperature disordered I41/acd phase is stabilized at room temperature, as this determines the properties of the system. Et4NHSO4 amorphization was also observed in the nanocomposites, with an increase in the matrix contents. The enthalpies of the endoeffects of salt melting and phase transitions (160 °C) changed more significantly than the Et4NHSO4 contents in the composites and completely disappeared at x = 0.9. The dependence of proton conductivity on the mole fraction reached a maximum at x = 0.8, which was three or four orders of magnitude higher than the value for pure Et4NHSO4, depending on the composition and the temperature. The maximum conductivity values were close to those for complete pore filling. The conductivity of the 0.2Et4NHSO4-0.8SiO2 composite reached 7 ∗ 10-3 S/cm at 220 °C and 10-4 S/cm at 110 °C.

Effective removal of highly toxic Pb2+ and Cd2+ ions using reduced graphene oxide, polythiophene, and silica-based nanocomposite

The purpose of this study is to develop a highly capable reduced graphene oxide, polythiophene, and silica-based low-cost composite material and investigate its adsorption behavior. The synthesized composite was analyzed using various analytical methods and applied to eliminate highly toxic metallic pollutants from contaminated water. Different adsorption parameters were used to decontaminate the wastewater. The best conditions for removing Pb2+ and Cd2+ ions were obtained. The adsorption efficiency was determined to be 65.9 (±0.9) % and 61.5 (±1.4) % at contact time of 60 minutes, 75.9 (±0.7) % and 76.1 (±0.8) % at 105 mg of adsorbent, 98.7 (±0.7) % and 93.2 (±0.6) % at pH 6 for Pb2+ and Cd2+ ions. The adsorbent was re-utilized up to three times with good adsorption effectiveness. A thermodynamic study has indicated the spontaneity of the adsorption process. The pseudo second order rate constant were found to be 19.1 (±1.5) and 16.5 (±1.7) g/mg/min for Pb2+ and Cd2+ ions, respectively.

One-pot self-assembly strategy to prepare mesoporous silica-based nanocomposites with enhanced and long-term antibacterial performance

Different from conventional polymer-modified antibacterial composites requiring multiple and complex synthesis processes, one-pot route was adopted in this work to prepare antibacterial nanocomposites (TTO@CTAB@MSNs) via a self-assembly strategy, which allowed the water-insoluble tea tree oil (TTO) to be encapsulated in the hydrophobic micelle core of cetyl trimethyl ammonium bromide (CTAB) within the nanochannels of mesoporous silica nanoparticles (MSNs). The chemical structures, pore structural parameters, and thermal stability of these nanocomposites were confirmed. It was found that, the obtained nanocomposites possessed a diameter below 600 nm with mesoporous structures. Although the increase in CTAB exerted slight influence on TTO content, it significantly enhanced the sustained release behavior of TTO. After continuously releasing for 8 h, the cumulative release rates only reached 20 %, and such release behavior followed the Zero-order kinetic model. Besides, these nanocomposites exhibited remarkable antibacterial performance against E. coli and S. aureus even at a low concentration of 0.06 mg mL−1 due to the collaboratively antibacterial effects from CTAB and TTO. And they maintained antibacterial activity even after 45 days, indicative of the long-term antibacterial performance. Moreover, the antibacterial mechanism of these nanocomposites was also elucidated assisting with the results of nucleic acid and conductivity measurements. Therefore, this work provides a facile one-pot self-assembly strategy to fabricate nanocomposites with remarkable antibacterial activity, and the long-lasting antibacterial performance make them a good candidate for actual applications.

A simple and universal strategy for construction and application of silica-based flame-retardant nanostructure

Inorganic-organic nanocomposites present excellent comprehensive performance due to the combination of the advantages of inorganic, organic, and nanotechnology. However, the preparation methods are usually complex and inefficient, especially not universal. Here, a simple and universal strategy was designed for preparing silica-based nanocomposite flame retardants . Mesoporous silica (m-SiO 2 ) was used to load ethylenediamine tetra(methylene phosphonic acid) (EDTMPA). Above the melting point of EDTMPA, molten EDTMPA enters into the mesoporous channels of m-SiO 2 by means of capillary force . After cooling, EDTMPA is fixed in the mesoporous cavity to form a flame retardant nanostructure containing silicon, phosphorus, and nitrogen (SiP). The whole process of mesoporous silica-loaded organic flame retardant is simple and green. Adding 3 phr SiP2 into epoxy (EP) resin can reduce the peak heat release rate , total smoke production, and peak CO production by 44.3%, 30.4%, and 45.5%, respectively. Besides, it shows good mechanical properties compared with the EP composites with physically blended m-SiO 2 and EDTMPA. These excellent performances are attributed to the combined effect of EDTMPA and m-SiO 2 as well as the nanoscale effect . This strategy provides a simple, efficient, and general method to prepare nanocomposites by loading molten organic compounds into m-SiO 2 . • A new universal strategy for preparing silica-based nanocomposite is developed. • Molten organic flame retardant was loaded into the channels of mesoporous silica. • A novel flame retardant containing silica, phosphorus, and nitrogen was obtained. • The flame retardant has better comprehensive properties than comparative samples. • The process of mesoporous silica-loaded organic flame retardant is simple and green.

Multifunctional mesoporous silica-based nanocomposites: Synthesis and biomedical applications

Nanotechnology is an emerging area of research for the exploitation of various scientific advancements for controlling material configuration at a reduced dimensional scale. With the advent of nanotechnology, a new era for the development of biological products has opened. Multifunctional mesoporous silica-based particles fulfil critical requisites for the preparation and characterization of nanotechnology products. Mesoporous silica nanoparticles (MSNPs) have distinctive structural features, such as large surface areas and tunable pore sizes, with particular suitability to deliver hydrophobic cargo intracellularly and tunable surface properties. Combinations of various nanostructured materials will enable the development of a multifunctional MSNP hybrid. Mesoporous silica nanoparticles have recently attracted much attention due to their significant potential for tumor treatment and imaging. Functionalized mesoporous silica materials have recently shown rapid growth in imagistic and curative applications. Multifunctional mesoporous silica nanocomposites have a higher capacity for drug loading and chemical release compared to amorphous colloidal silica. Therefore, MSNPS is an ideal platform for constructing multipurpose tools that incorporate various functional nanostructured materials. This review summarized the most recent advances in mesoporous materials research and discussed the use of various nanocarriers conjugated with MSNPs. High potential characteristics and exciting practical applications highlight different manufacturing strategies for these hybrids (noble metals, carbohydrates, up-conversion and magnetic nanoparticles (NPs), quantum dots (QDs), and photodynamic therapy (PDT)).

Investigation of the influence of the energy conditions of pulsed plasma-chemical synthesis on the morphological and structural properties of copper-containing silica-based nanocomposites

Abstract This paper presents the results of a study of the effect of energy conditions (additional heating of the walls of the reaction chamber and subsequent action of an electron beam on the synthesized powder) of pulsed plasma-chemical synthesis on the morphology, average geometric size, phase and chemical composition of copper-containing silica-based nanocomposites. The nanocomposites were synthesized using a TEA-500 pulsed electron accelerator. It was the first time that copper-containing silica-based nanocomposites had been prepared using the pulsed plasma-chemical synthesis. The values of the band gap for the as-prepared nanocomposites were calculated. The nanocomposites were characterized by means of transmission electron microscopy and X-ray diffraction. The analysis revealed the changes in the morphology and phase composition of the nanocomposites upon energy conditions.

Preparation of mesoporous silica-based nanocomposites with synergistically antibacterial performance from nano-metal (oxide) and polydopamine

In this work, a novel antibacterial nanocomposite system was developed using mesoporous silica (MSN) as an effective nanocarrier, and the resultant nanocomposites demonstrated remarkable antibacterial performance due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine (PDA). The successful synthesis of MSN/ZnO@PDA/Ag nanocomposites was confirmed. The physicochemical properties and the morphologies of these nanocomposites were investigated. It was found that the particle size increased along with the evolution of these nanocomposites. Besides, nano zinc oxides were formed in the nanochannels of mesoporous silica with a particle size about 2 nm, and that of silver nanoparticle was less than 50 nm. In addition, the results revealed that the presence of mesoporous silica could effectively prevent the formation of large-size silver nanoparticles and facilitate their well dispersion. Due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine, these nanocomposites exhibited remarkable antibacterial performance even at a low concentration of 313 ppm, and the antibacterial mechanism was also elucidated. Therefore, this work provides a facile and controllable approach to preparing synergistically antibacterial nanocomposites, and the remarkable antibacterial performance make them suitable for practical applications.

A Review of Engineering Dielectric Properties of Nanocomposites through Effectively Removed Interfacial Water

The current work reviews the importance of engineering the interface between nanofillers and polymers to achieve unique dielectric properties in nanocomposites. Although many improved dielectric properties of nanocomposites have been attributed to the presence of the interface, the interface can also be an attractive location for water to accumulate, which may otherwise jeopardize the dielectric properties of nanocomposites. Consequently, the use of surface functionalization and calcination techniques in removing water-related moieties on nanofillers is highlighted. Specifically, the effects of nanofiller calcination on two exemplar oxide-based nanocomposite systems, namely, silica-based nanocomposites and zirconia-based nanocomposites, are discussed. Evidence suggests that nanofiller calcination influences not only the water-related chemistry, but also the structure of oxide-based nanofillers. Significantly, for detailed interfacial chemistry of nanofillers to become relevant in engineering the dielectric properties of nanocomposites, effective removal of interfacial water on nanofillers is crucial.

Preparation and characterisation of Ce-doped SiO2 nano-materials as effective photo-catalyst under visible light

ABSTRACT A series of silica-based nanocomposites have been synthesised by an impregnation and co-impregnation method, namely, 20 wt% Ti-SiO2, 20 wt% Ce-SiO2, 20Ti-Ce-SiO2 (10:10 wt/wt Ti:Ce), and 40Ti-Ce-SiO2 (20:20 wt/wt Ti:Ce). The prepared photocatalysts have been characterised by XRD, SBET, FT-IR, FE-SEM, XPS and optical techniques. The activity of the prepared photo-catalysts was evaluated using Fuchsine acid dye under UV and visible exposure. The degradation percentage and apparent first-order kinetics were calculated. The photo-degradation of the nano-composites was reached 62%, 84.8%, 79% and 73% for Ti-SiO2, Ce-SiO2, 20Ce-Ti-SiO2 and 40Ce-Ti-SiO2 after 180 min under visible irradiation. The scavenger’s assessment analysis was carried out to know the vital role of responsive species which responsible for photoactivity. The Ce-SiO2 exhibited an excellent photocatalytic activity of Fuchsine acid (FA) dye degradation under visible light. The photo-degradation rate (k) of the synthesised samples was 1.1 × 10−2 min−1 with R2 of 0.98 for Ce-SiO2 photo-catalyst. The results confirmed that the h+ and O2 •− principally participate in the photodegradation of dye over Ce-SiO2 nano-composite; however, •OH contributes in negligible extent.

SPION-decorated organofunctionalized MCM48 silica-based nanocomposites for magnetic solid-phase extraction

(a) Cubic structures formed by CTAB above critical micellar concentration used as a template to generate highly ordered mesoporous silica. (b) Photo showing the magnetic recovery of MCM48/SPION/C8 nanocomposite in 60 s.

The impact of the functionalization of silica mesopores on the structural and biological features of SBA-15

Hydrophobic and hydrophilic silver-functionalized SBA-15 silica nanocomposites were prepared via direct synthesis using the so-called BOTTOM-UP approach to nanotechnology. This process enables silica-based nanocomposites with a controlled metal content to be fabricated. XRD, XPS, Raman, SEM-EDX and TEM methods were used to describe the physicochemical properties of these systems. The surface atomic content of silver (XPS) was estimated at approximately 0.03 at.% and 0.04 at.% compared to the bulk signal (SEM-EDX), which was determined to be about 0.33 at.% and 0.48 at.%, respectively for the non-silylated and silylated systems. The XPS studies that were carried out for these two structures revealed the presence of elemental and/or oxidized silver on the surfaces. However, in the more volumetric XRD studies, there was no clear signal that corresponded to this metal, which suggests the presence of an ionic form of silver. Calcination was used to obtain the silver-decorated porous silica ceramic composites, for which the calcination temperature was determined from TGA/DTG studies. The calcination resulted in the compensation of the surface and bulk atomic content of silver at approximately 0.1 at.% (on both the surface and the bulk). The wettability measurements classified silylated specimens as well as silylated and calcined systems as being hydrophilic and hydrophobic, respectively. Low-angle diffraction confirmed the mesoporous character of the silica with hexagonal pore channels regardless of the degree of functionalization or calcination. The Raman data illustrated the impact of the silver on the propyl-carbonate chains and silica structure. Finally, the most vigorous bactericidal activity was found against Staphylococcus aureus and Escherichia coli for a hydrophilic system with a low silver content and a calcined sample with a slightly higher silver concentration. • Development of the hydrophobic and hydrophilic materials with homogeneously distributed metal (M = Ag + ) ions. • Impact of mesopores functionalization on the structure and biological effect. • Impact of the temperature on the structural and biologic features of the mesopores systems.