Surface Modification Of SiO2 Nanoparticles Research Articles

Effects of nano-smart water on enhanced oil recovery in carbonate reservoirs: Interfacial tension reduction and wettability alteration

Several studies have revealed that nanofluid and smart water flooding are cost-effective methods, considering the effect of nanoparticles and potential determining ions (PDIs) for enhanced oil recovery in carbonated reservoirs. This study presents the performance of nano-smart water synthesized with surface-modified SiO2 nanoparticles dispersed in PDI-controlled seawater (SW), ensuring dispersion stability in high-temperature and high-salinity reservoirs. The interfacial tension (IFT) and contact angle of the oil/nano-smart water/carbonate rock system were measured using kerosene as an oil phase. At this time, nanoparticle concentrations ranged from 0.5 to 3 wt% and PDI concentrations ranged from 1,000 to 5,000 ppm, such as KCl, MgCl2, MgSO4, and K2SO4. In addition, the IFT and contact angle of SW, low salinity water (LSW), and nanofluid were measured for comparison. It was observed that at nanoparticle concentrations higher than 1 wt%, the IFT values of nano-smart water remained constant or decreased slightly to below 31.91 mN/m compared with nanofluids at 32.18 mN/m, regardless of PDI type and concentration. This indicates that using nano-smart water instead of LSW and SW is expected to reduce the IFT in the oil/water system. The contact angle measurements revealed that the wettability index is 2.57–5.07 times higher in nano-smart water than in nanofluids. This implies that wettability alteration is accelerated by the synergistic effect of PDIs and nanoparticles. Specifically, PDI control with MgSO4 or K2SO4 is highly effective in changing the contact angle of carbonate from strongly oil-wet to strongly water-wet due to the ion exchange reaction of SO42- in oil/water/carbonate rock system. The nano-smart water used in this study is expected to be utilized as an injection fluid under harsh conditions for enhanced oil recovery.

The influence of doping with different surface modified SiO2 nanoparticles on the dielectric properties of natural ester insulating oil

Nanoparticles are presently considered to be high-potential filler materials in insulation medium. Surface-modified nanoparticles can not only improve the compatibility between nanoparticles and insulation liquid but also enhance the dielectric properties. Herein, models of soybean oil-based natural ester insulation oil doped with two silane coupling agents (A151, KH550) modified SiO2 were established, respectively. Molecular dynamics and DFT first principles were applied to explore the effect of two nanoparticles on the dielectric properties of liquid-insulation medium. The results showed that two types of nanoparticles can restrict the diffusion of water molecules by forming hydrogen bonds, while the number of hydrogen bonds in KH550–SiO2 is one-third more than that in A151-SiO2, and the interaction energy is lower, demonstrating a stronger adsorption effect on water molecules. Moreover, surface electrostatic potential and frontier molecular orbitals showed that KH550–SiO2 have a higher adsorption on charged particles in natural ester insulation oil, which can further inhibit the development of streamer discharge in the liquid insulation medium, improve its dielectric property and delay the aging and deterioration of natural ester insulation oil. This study extends our knowledge into the influence of silane coupling agents modified SiO2 nanoparticles on the dielectric performance of liquid insulation materials from a microscopic perspective.

Influence of MgO and Surface Modified SiO2 Nanoparticles on Emulsion Stability, Rheology, Energy Consumption, and Mobility of East Baghdad Crude Oil

Influence of MgO and Surface Modified SiO2 Nanoparticles on Emulsion Stability, Rheology, Energy Consumption, and Mobility of East Baghdad Crude Oil

Surface modification boosts dispersion stability of nanoparticles in dielectric fluids

Achieving stable dispersion of nanoparticles in dielectric fluids is a challenging task, as there are complex and diverse influencing factors, requiring molecular-level understanding of the nanoparticle aggregation. In this paper, we conducted long-time molecular simulations of dielectric nanofluids containing fifteen SiO2 nanoparticles, systematically varying the length of alky chains grafted onto their surface to explore their impact on the aggregation process. Our results reveal that appropriate surface modification can dramatically increase the dispersion stability of nanoparticles in dielectric fluids. SiO2 nanoparticles lacking alkyl chains exhibit a strong tendency to approach each other, and form aggregates in natural esters, because of the Coulombic energy from heteroatoms of SiO2 nanoparticles. Despite the differences in the length of grafted alkyl chains on the surface of SiO2 nanoparticles, all of them, regardless of their length, are capable of effectively shielding the Coulombic interactions and increasing the van der Waals interaction with natural esters, thereby reducing the aggregation tendency of nanoparticles. Furthermore, the smaller diffusion ability, caused by the steric hindrance effect, of surface-modified SiO2 nanoparticles also inhibits their collision and subsequent aggregation.

Surface modification of silica nanoparticles by chitosan for stabilization of water-in-oil Pickering emulsions

Water-in-oil (W/O) Pickering emulsions (PEs) as delivery systems have recently attracted important research efforts. The lack of food-grade hydrophobic particulate as emulsion stabilizers is the most important challenge in this field. This study investigates the surface modification of silica (SiO2) nanoparticles (SNPs) by chitosan and their role in formulation and stabilization of PEs; namely, the adsorption of chitosan on the surface of SNPs through electrostatic attraction with different chitosan/SiO2 ratio and pH values. The ability of SNPs to stabilize water in oil PEs regarding this modification was then investigated. The interaction between SNPs and chitosan was characterized by zeta potential, wettability, FTIR, Energy dispersive X-ray mapping analysis (EDX- MAP) and nitrogen absorption/desorption isotherm. The results confirmed that the surface modification of SNPs by chitosan had a significant impact on zeta potential and on the wettability of SNPs. Finally, modified SNPs were applied to the formulation of PEs; we identified the optimized conditions that increase the emulsion formulation process and stability. Therefore, modified SNPs by chitosan in this study could act as food-grade W/O Pickering stabilizers to fabricate environmental-friendly emulsion products.

Effect of Non-Modified as Well as Surface-Modified SiO2 Nanoparticles on Red Blood Cells, Biological and Model Membranes.

Nanoparticles are extremely promising components that are used in diagnostics and medical therapies. Among them, silica nanoparticles are ultrafine materials that, due to their unique physicochemical properties, have already been used in biomedicine, for instance, in cancer therapy. The aim of this study was to investigate the cytotoxicity of three types of nanoparticles (SiO2, SiO2-SH, and SiO2-COOH) in relation to red blood cells, as well as the impact of silicon dioxide nanoparticles on biological membranes and liposome models of membranes. The results obtained prove that hemolytic toxicity depends on the concentration of nanoparticles and the incubation period. Silica nanoparticles have a marginal impact on the changes in the osmotic resistance of erythrocytes, except for SiO2-COOH, which, similarly to SiO2 and SiO2-SH, changes the shape of erythrocytes from discocytes mainly towards echinocytes. What is more, nanosilica has an impact on the change in fluidity of biological and model membranes. The research gives a new view of the practical possibilities for the use of large-grain nanoparticles in biomedicine.

Molecular level investigation on the dispersion of hydrophilic modified SiO2 nanoparticles in water from a bond energy viewpoint

AbstractThe dispersion characteristic of nanoparticles is of more interest in some engineering applications, including polymer filling, foam stability, chemical catalysis, and materials surface package. In this paper, the surface modification of SiO2 nanoparticles was carried out based on molecular dynamics simulation. The characteristics of aggregation and diffusion of SiO2 nanoparticles were explained by the radial distribution function (RDF), concentration profile, length distribution, mean squared displacement (MSD), and microscopic testing (MT). The results showed that the orbital provided by the three types of atoms (H, O, and Si) corresponding to the different bandwidths caused the energy alternation of state density. According to the results of RDF, the HO bond energy mainly provided by the water molecules showed the maximum bond energy with 463 kJ/mol. The results indicated that the bonds breakage and formation were accompanied by changes in total energy, kinetic energy, non‐bond energy, and potential energy. After the modification of SiO2 nanoparticles, the concentration profile of the water molecules decreased first at 1–8.5 Å and then increased at 8.5–17.2 Å, but the length distribution climbed to 15.7 at 0.975 Å. When the temperature reached 398 K, the peak value of the length distribution declined to 13.6 Å and the relative concentration profile of water molecules fluctuated around 1.0. With the increase of salinity, the peak value of length distribution reached 15.7 at 0.975 Å, but the concentration profile of water molecules at 3.1–9 Å decreased quickly and then gradually increased. The results of MSD and MT about water molecules presented the largest diffusion coefficient appeared at 398 K and had the best dispersion effect owing to the average kinetic energy among the molecules. Conversely, the diffusion coefficient decreased with the incremental solution salinity because the inhabitation of sodium for the motion of water molecules resulted in the ion bridging and hydrogen bonding.

Experimental Investigation of Rheological Properties and Thermal Conductivity of SiO2-TiO2 Composite Nanofluids Prepared by Atomic Layer Deposition.

In the current research, surface-modified SiO2 nanoparticles were used upon immersion in an applied base fluid (ethylene glycol:water = 1:1). The atomic layer deposition method (ALD) was introduced to obtain a thin layer of TiO2 to cover the surface of SiO2 particles. After the ALD modification, the TiO2 content was monitored by energy dispersive X-ray spectroscopy (EDS). Transmission electron microscopy (TEM) and FT-IR spectroscopy were applied for the particle characterization. The nanofluids contained 0.5, 1.0, and 1.5 volume% solid particles and zeta potential measurements were examined in terms of colloid stability. A rotation viscosimeter and thermal conductivity analyzer were used to study the nanofluids’ rheological properties and thermal conductivity. These two parameters were investigated in the temperature range of 20 °C and 60 °C. Based on the results, the thin TiO2 coating significant impacted these parameters.

Preparation of Pickering Emulsions Stabilized by Modified Silica Nanoparticles via the Taguchi Approach.

In this study, oil-in-water Pickering emulsions (PEs) were prepared by modified silica nanoparticles (MSNs) with cetyltrimethylammonium bromide (CTAB) using the Taguchi approach. The surface modification of SiO2 nanoparticles (NPs) was performed in different conditions, temperatures, pH levels, and amounts of CTAB as a coating agent, followed by an evaluation of their physicochemical properties. After treatment of the SiO2 NPs, the relationship of the MSNs’ surface properties and their efficiency in stabilizing Pickering emulsions was investigated by considering the zeta potential (ZP) and emulsion physical stability as main responses, respectively. Results disclosed were then supported by additional characterization, such as thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, contact angle (CA), and scanning electron microscopy. Results demonstrated that temperature has the most important role in the treatment of SiO2 nanoparticles, and allows for the identification of the best experimental conditions, i.e., range of zeta potential of MSNs to produce more efficient NPs, as well as the best stabilization of PEs.

Surface modification of SiO2 nanoparticles for bacterial decontaminations of blood products

Bacterial infections can be caused by contamination of labile blood products with specific bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis. Hospital equipment, bio-protective equipment, delivery systems, and medical devices can be easily contaminated by microorganisms. Multidrug-resistant bacteria can survive on various organic or inorganic polymeric materials for more than 90 days. Inhibiting the growth and eradicating these microorganisms is vital in blood transfusion processes. Blood bags and other related medical devices can be improved by the incorporation of organic or inorganic nanomaterials, particularly silicon dioxide (SiO2) nanoparticles. The addition of solid organic or inorganic nanoparticles to synthetic polymers or biopolymers can provide new properties in addition to antimicrobial activity. Among these NPs, formulations composed of SiO2 nanoparticles and polymers have been shown to improve the mechanical and antimicrobial properties of catheters, prosthetic inserts, blood bags, and other medical devices SiO2 nanoparticles possess several advantages, including large-scale synthetic availability, simple one-pot synthesis methods, porous structure for loading antibacterial agents, good biocompatibility, and thermal stability. Plasticized polyvinyl chloride is the main polymer, which has been functionalized by these nanoparticles. In this review, we discuss the recent advances and challenges regarding the functionalization of polyvinyl chloride by SiO2 nanoparticles to hinder bacterial contaminations in blood products.

Preparation of Superhydrophobic/Superoleophilic nitrile rubber (NBR) nanocomposites contained silanized nano silica for efficient oil/water separation

Nowadays, the superhydrophobic/superoleophilic nanocomposites has attracted considerable interests due to their unbeatable properties for oil–water separation. In this research, nitrile rubber (NBR) was used as oil sorbent due to its high elasticity under stresses and high resistance to organic solvents and fuels. To increase its oil absorption capacity, silica nanoparticles were silanized by vinyltriethoxysilane (VTES) at suitable silane concentration and added to a NBR compound. The surface modified nanoparticles were characterized by TGA, FTIR, XPS, SEM-EDX and XRD analysis as well as contact angle test to assess successful grafting of silane to the nanoparticles surface. The effects of nanoparticles on contact angle, oil absorption capacity, oil recovery efficiency of NBR samples was also studied. It was found that silanized nano silica caused considerable increment in the contact angle from 41 and 89.8° (i.e. for pure nano silica containing and pristine NBR samples, respectively) to 153°. It was specified that the nanocomposite increased oil absorption capacity of NBR up to four times. It was also found that the rubbery nanocomposite contained surface modified SiO2 nanoparticles retained 95% of oil recovery efficiency even after 1000 oil absorption/desorption cycles. The mechanical and dynamic mechanical properties of NBR compounds were also evaluated. The modified silica nanoparticles improved the thermomechanical properties of nitrile rubber and developed a high performance superhydrophobic/superoleophilic elastomeric material for oil/water separation.

The Effect of 3-(Glycidoloxy Propyl) Trimethoxy Silane Concentration on Surface Modification of SiO2 Nanoparticles

SiO2 is widely used in nanocomposites as reinforcement nanoparticle to enhance mechanical properties especially wear resistivity. Prior to use, surface modification with proper and sufficient coupling agent should be performed on it. Coupling agent concentration plays a key role in modification process. In this study, the influence of 3-(glycidoloxy propyl) trimethoxy silane (GPTMS) concentration on surface modification of SiO2 nanoparticles, is experimentally investigated. The surface modification of nano-silica were performed by 30, 50, 80 and 110 wt.% of GPTMS in order to introduce the optimal GPTMS concentration to complete the process. Fourier Transformation Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Thermo Gravimetric Analysis (TGA) and X-Ray Diffraction (XRD) characterized the pure and surface modified samples; then, the results were compared to each other to achieve the aim of the research. FTIR results confirmed the silanization proceed due to the silane absorption peak disappearing and shifting of the hydroxyl group bonds in to the amide bonds. This test showed that 30 wt.% GPTMS has not been sufficient for full functionalization of the NPs. According to FESEM images, it seems that the NPs were better modified by 80 wt.% GPTMS due to the least NPs aggregation and lack of coupling agent deposition on the NPs. Also, TGA illustrates that this sample has higher thermal stability because of lower weight loss (11.2%) in coupling agent decomposition temperature range: 130–380 °C. Furthermore, X-Ray Diffraction confirmed the FESEM and TGA results about the mentioned sample due to its highest crystallite size (increase 26.64% in crystallite size in comparison with the pure sample). So, the 80 wt.% of GPTMS introduced as the optimal concentration for surface modification of SiO2 nanoparticles.

Effect of surface modification of dispersoid on hybrid polymer electrolyte

This study reports the properties of hybrid polymer electrolyte films obtained via incorporating varying amounts of surface modified SiO2 nanoparticles and electrolyte solution (1 M LiBF4 in EMIMBF4) in PVdF-HFP. The SiO2 nanoparticles (diameter ~100–150 nm) have been synthesized by the conventional Stober's method and further modified chemically in two steps, viz., (i) carboxylation and (ii) EDC-NHS coupling. The surface modification of the nanoparticles has been confirmed by FTIR and XRD. The effect of addition of modified SiO2 and/or electrolyte solution has been studied using different characterization techniques. The positive impact of surface modification is evident by the reduced aggregation of the surface modified nanoparticles in the host matrix as compared to the unmodified ones (SEM micrographs). The effect of better dispersion of the modified nanoparticles in the polymer matrix has been reflected by the enhanced ionic conductivity (at room temperature) of modified SiO2 added electrolyte film (~2.94 mS/cm) compared to the films with no SiO2 and unmodified SiO2 (~1.90 mS/cm and ~1.56 mS/cm, respectively). The hybrid electrolyte film with maximum ionic conductivity has exhibited a wide electrochemical stability window (~5.5 V) and good mechanical and thermal stability (up to ~300 °C). The optimized hybrid film has been further used to fabricate an electric double layer capacitor (EDLC). The electrochemical performance of the cell has been studied using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques.

The surface modification and characterization of SiO2 nanoparticles for higher foam stability

The surfactant and colloidal nanoparticles has been considered for various applications because of interaction of both complex mixtures. The hydrophilic SiO2 nanoparticle could not be surface active behavior at the liquid/air interface. In this study, the SiO2 nanoparticles have been modified with 3-isocyanatopropyltriethoxy-silane (ICP), and the effect of foam stability has been investigated. The physical properties of surface modified SiO2 nanoparticle were analyzed by XRD, TGA, FT-IR, and SEM. After surface modification of SiO2 nanoparticles, the contact angle of SiO2 nanoparticle was also increased from 62° to 82° with increased ICP concentration. The experimental result has shown that SiO2 nanoparticle with ICP was positive effect and improved foam stability could be obtained at proper ICP concentration compared with un-modified SiO2 nanoparticle.

Long-lasting intrinsic polyethylene antifogging films generated by incorporating SiO2 nanoparticles into covalently grafted antifog agents

Antifogging films are used in an increasing number of applications in greenhouse cultivation because fog formation affects transmission. Here, we summarize a way to improve the antifogging duration of linear low-density polyethylene (LLDPE) films by controlling the migration of the antifog agent. We prepared SiO2-grafted glycerin monostearate (SiO2-g-GMS) by covalently grafting surface modified SiO2 nanoparticles and glycerin acrylic acid monostearate (GMS-AA). Then, SiO2-g-GMS was added in LLDPE, and antifogging films were prepared for study of their properties. The reaction with modified SiO2 and GMS-AA was demonstrated by Fourier transform infrared spectroscopy, thermogravimetric analysis and grafting degree (GD). The GD of SiO2-g-GMS was approximately 54.95%. Accelerating dripping experiments and contact angle measurements illustrated that GMS-AA-grafted modified SiO2 exhibited delayed migration of the antifog agent, prolonging the antifogging duration by approximately 3 days. We determined that 3 wt% SiO2-g-GMS was a suitable proportion, considering economy and the desired properties. The SEM images indicate that dispersion of SiO2-g-GMS in the film was extensive, and the particle size was 160 ± 40 nm. In addition, the study also showed how modified SiO2 grafted with GMS-AA does not affect the processes and usability of antifogging films.

Surface modification of SiO2 nanoparticles with PDMAEMA brushes and Ag nanoparticles as antifungal coatings using electron beam assisted synthesis

A model functional, stable and dispersible silver nanoparticles (AgNPs) immobilized on polymeric brushes grafted silica nanoparticle is proposed as antimicrobial additive for coating applications. The aim of this work is to modify silica nanoparticles (SiO2NPs) with poly 2-(dimethyl amino) ethyl methacrylate (PDMAEMA) brushes for template synthesis and immobilization of AgNPs using electron beam assisted grafting and reduction reactions. The PDMAEMA moieties were grafted onto vinyltrimethoxysilane (VTMS) modified SiO2NPs using pre-irradiation and peroxidation grafting approaches. Several grafting parameters, i.e., pre-irradiation doses, DMAEMA monomer concentrations, reaction times and temperatures, were studied to optimize degree of grafting (DG). AgNPs were constructed on the SiO2NPs through the grafted PDMAEMA brushes as polymer shell template. AgNPs were successfully created on SiO2NPs-VTMS-PDMAEMA by electron-induced reduction reaction. DG of the PDMAEMA on SiO2NPs-VTMS was confirmed by gravimetric measurement, FTIR, TGA, TEM, FE-SEM. The nanostructure information and AgNPs immobilization were revealed by UV–Vis, TEM, SEM-EDX and XRD. The optimized grafting degree to obtain desirable appearance was 190%. The AgNPs (6 ± 2 nm) on SiO2NPs-VTMS-PDMAEMA exhibited the characteristic UV-vis absorbance of spherical Ag nanoarchitecture around 418 nm. The AgNPs immobilized SiO2NPs-VTMS-PDMAEMA efficiently inhibited the growth of fungi, i.e., Aspergillus niger and Syncephalatrum racemosum found on building materials.

Guanidine-Functionalized Amphiphilic Silica Nanoparticles as a Pickering Interfacial Catalyst for Biodiesel Production

A series of surface-modified SiO2 nanoparticles (NPs) were designed and prepared by combining a guanidine group (1,1,3,3-tetramethylguanidine [TMG]) as the base catalytic functionality and n-alkyl ...

A novel cross-linked nanocomposite solid-state electrolyte with super flexibility and performance for lithium metal battery

Solid-state electrolyte batteries are considered as one of the promising next generation power sources. A novel cross-linked nanocomposite polymer electrolyte (CNPE) based on poly (propylene oxide)-poly (ethylene oxide)-poly (propylene oxide) triblock main chains and surface-modified SiO2 nanoparticles are prepared to establish a super flexible and stable polymer framework. The CNPE exhibits high ionic conductivity of 1.32 mS cm−1 at 20 °C and its electrochemical stability window reaches up to 6.5 V (versus Li+/Li). The favorable Li deposition behavior provided by CNPE films is identified by the stripping/plating test at a current density of 2.4 mA cm−2 for 1700 h. The CNPE films possess excellent mechanical stability (highly stretchable with ultimate elongation of 700%). Li/CNPE/LiFePO4 batteries deliver an initial discharge capacity of 160 mAh g−1 at 0.2 C, which is 94.1% of the theoretic capacity, and maintain the high specific capacity of 148 mAh g−1 at 0.5 C. This work provides a new approach toward designing high performance electrolyte for lithium metal batteries.

Applications of silica nanoparticles in glass/carbon fiber-reinforced epoxy nanocomposite

Abstract Fiber-reinforced polymer nanocomposite has attracted significant attention in recent years due to its superior mechanical properties, outstanding lightness in weight, good thermal stability and corrosion resistance ability, which is enhanced by a variety of organic and/or inorganic nanofillers. Among all available inorganic nanofillers, silica (SiO2) nanoparticle (SNP) is one of the most important nanofillers and found at the forefront in the field of polymer composite materials due to its abundance and high-performance features. This is a tutorial review on the advances made in fabrication and application of glass/carbon fiber-reinforced epoxy nanocomposite (GFRENC/CFRENC) with SNPs and surface-modified SNPs. Research attempts on surface modification of SNPs and strategies to achieve high performance SNP-enhanced GFRENC/CFRENC are addressed.

Demulsification of water in oil emulsion by surface modified SiO2 nanoparticle

In the present study, SiO2 nanoparticles (NP) were used for dehydration of crude oil. Also, in order to enhance the hydrophobicity and hydrophilicity of the nanoparticles, they were functionalized respectively with oleic acid (OA) and sodium dodecyl benzene sulfonate (SDBS) surfactant. Furthermore, graphene oxide (GO) was employed to synthesis GO-SiO2 nanocomposite as a superhydrophilic demulsifier. Nanodemulsifiers were characterized with scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and zeta potential. Additionally, the performance of nanodemulsifiers was evaluated with bottle test. The results of bottle test revealed that GO-SiO2 nanocomposite has the best performance among all nanodemulsifiers and dehydration of crude oil was completed during 90 min (while dehydration of crude oil with SiO2 nanoparticle was done at 110 min). Moreover, the effects of temperature and salt were surveyed and the results demonstrated that both factors influence the stability of water in oil emulsion. The outcomes of the interfacial tension (IFT) at the water/crude oil interface displayed GO-SiO2 nanocomposite has interface active property and can decrease IFT from 14.38 mN m−1 to 2.44 mN m−1.