Surface-modified Silica Nanoparticles Research Articles

Composition-Orientation Induced Mechanical Synergy in Nanoparticle Brushes with Grafted Gradient Copolymers.

Gradient poly(methyl methacrylate/n-butyl acrylate) copolymers, P(MMA/BA), with various compositional ratios, were grafted from surface-modified silica nanoparticles (SiO2-g-PMMA-grad-PBA) via complete conversion surface-initiated activator regenerated by electron transfer (SI-ARGET) atom transfer radical polymerization (ATRP). Miniemulsion as the reaction medium effectively confined the interparticle brush coupling within micellar compartments, preventing macroscopic gelation and enabling complete conversion. Isolation of dispersed and gelled fractions revealed dispersed particle brushes to feature a higher Young's modulus, toughness, and ultimate strain compared with those of the "gel" counterparts. Upon purification, brush nanoparticles from the dispersed phase formed uniform microstructures. Uniaxial tension testing revealed a "mechanical synergy" for copolymers with MMA/BA = 3:2 molar ratio to concurrently exhibit higher toughness and stiffness. When compared with linear analogues of similar composition, the brush nanoparticles with gradient copolymers had better mechanical properties, attributed to the synergistic effects of the combination of composition and propagation orientation, highlighting the significance of architectural design for tethered brush layers of such hybrid materials.

Performance evaluation of surface-modified silica nanoparticles for enhanced oil recovery in carbonate reservoirs

The purpose was to prepare a (3-glycidoxypropyl)-trimethoxysilane (GPTMS)-SiO2 nanofluid and analyze the effect of nanofluid injection on carbonate reservoirs. GPTMS-modified silica nanoparticles (SNPs) were investigated by Fourier transform infrared spectroscopy (FTIR) and elemental analysis. FTIR spectra of C-H stretching vibrations at 2950 cm−1, indicating silica surface modification with GPTMS, were observed when the GPTMS in the feed was greater than 0.7 mmol/g. Further, a stable nanofluid was obtained when the amount of grafted silane was close to 0.73 mmol/g, the theoretical maximum amount of grafted silanes. To evaluate the performance of surface-modified SNPs for enhanced oil recovery in carbonate reservoirs, wettability alteration tests comprising flotation test and contact angle measurements using powder and plug samples of carbonates, respectively, were performed with different SNP concentrations. Powder samples were successfully changed from oil-wet to water-wet, and the contact angle of the plug sample decreased by up to 62.8% as a result of the reaction of the nanofluid; however, it did not reduce interfacial tension (IFT) as effectively as IFT reducer additives. A coreflooding test was conducted to determine the effective parameters of the enhanced oil recovery with the GPTMS-nanofluid, such as SNP concentration, injection rate, and rock properties. The nanofluid injection increased oil recovery by approximately 20% compared to conventional waterflooding through incremental oil recovery, mainly attributed to wettability alteration. Therefore, we expect the nanofluid to dramatically increase the oil recovery in strongly oil-wet carbonate reservoirs under high-salinity conditions.

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.

Effects of silica surface modification with silane and poly(ethylene glycol) on flexural strength, protein-repellent, and antibacterial properties of acrylic dental nanocomposites.

The main aim of the current work was to develop dental acrylic-based composites with protein-repellent and antibacterial properties by using surface-modified silica nanoparticles. The effects of surface modification of silica nanoparticles in protein-repellent and antibacterial activity and mechanical properties of dental composites including flexural strength, flexural modulus, and hardness were discussed. The surface of silica nanoparticles was first chemically treated with 3-methacryloxypropyltrimethoxysilane (MPS) as a coupling agent and then with poly(ethylene glycol) (PEG) bonded to MPS. Dental acrylic-based composites were prepared with mass fractions of 10, 15, 20, 30, and 40% of PEG-modified MPS-silica nanoparticles (PMS). The chemical surface modification of silica nanoparticles with MPS and PEG was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The dental composite containing 20wt% PMS nanoparticles could reduce the protein adsorption by 28% as compared with a composite containing 20wt% MPS-modified silica. The antibacterial test indicated that the PMS nanoparticles can significantly reduce the adhesion of Streptococcus mutans and the biofilm formation on the surface of dental composites. It was found that the flexural strength increased by increasing the PMS nanoparticles from 0 to 20wt% and then decreased by the incorporation of higher percentages of these nanoparticles. Also, with increasing the weight percentage of PMS nanoparticles, the elastic and the flexural modulus and the hardness of resin nanocomposites were increased. In the current work, for the first time, dental resin composites containing PEG were prepared with excellent protein-repellent and antibacterial properties.

Virus-like Silica Nanoparticles Improve Permeability of Macromolecules across the Blood-Brain Barrier In Vitro.

The presence of the blood-brain barrier (BBB) limits the delivery of therapies into the brain. There has been significant interest in overcoming the BBB for the effective delivery of therapies to the brain. Inorganic nanomaterials, especially silica nanoparticles with varying surface chemistry and surface topology, have been recently used as permeation enhancers for oral protein delivery. In this context, nanoparticles with varying sizes and surface chemistries have been employed to overcome this barrier; however, there is no report examining the effect of nanoscale roughness on BBB permeability. This paper reports the influence of nanoscale surface roughness on the integrity and permeability of the BBB in vitro, using smooth surface Stöber silica nanoparticles (60 nm) compared to rough surface virus-like silica nanoparticles (VSNP, 60 nm). Our findings reveal that VSNP (1 mg/mL) with virus-mimicking-topology spiky surface have a greater effect on transiently opening endothelial tight junctions of the BBB than the same dose of Stöber silica nanoparticles (1 mg/mL) by increasing the FITC-Dextran (70 kDa) permeability 1.9-fold and by decreasing the trans-endothelial electrical resistance (TEER) by 2.7-fold. This proof-of-concept research paves the way for future studies to develop next-generation tailored surface-modified silica nanoparticles, enabling safe and efficient macromolecule transport across the BBB.

Understanding directed assembly of concentrated nanoparticles at energetically heterogeneous interfaces of cholesteric liquid crystal droplets

Colloidal self-assembly has gained significant interest in scientific and technological advances. We investigated the self-assembly of the colloids at fluidic interfaces that mediate elastic interactions. Whereas past studies have reported the assembly of micrometer- or molecular-sized species at aqueous interfaces of liquid crystals (LCs), herein we study the assembly of intermediate-sized nanoparticles. Specifically, surface-modified silica nanoparticles (50 to 500 nm) were adsorbed at the liquid crystal-water interfaces and their positioning was investigated using electron microscopy after polymerization. The study revealed that the electric double layer forces and the elastic forces caused by LC strain are dominant in the assembly of nanoparticles and their contributions can be tuned to direct the self-assembly guided by the sub-interface symmetry of confined cholesteric LCs. At high ionic strengths, we observed a strong localization of nanoparticles at the defects, whereas intermediate strengths resulted in their partial enrichment into cholesteric fingerprint patterns with an interaction energy of ≈3 kBT. This result is comparable with the calculations based on the strength of the binary interactions of the nanoparticles. The findings also support the role of ion partitioning at the LC-aqueous interfaces on the formation of the assemblies. The results can be utilized for applications in sensors, microelectronics, and photonics.

Surface Modification of Silica Nanoparticles with Ethyl Oleate for the Purpose of Stabilizing Nanolubricants Used for Tribological Tests

Long-term sustainability and decreasing amount of fossil oil reserves require a partial or complete transformation of traditional lubricating oils. The use of silica nanoparticles as a lubricant additive has a huge tribological potential, which has already been discussed in numerous articles. Nanosized silica shows excellent results in reducing friction and preventing wear, but they quickly aggregate and settle after homogenization in oils. For long-term stable dispersion of lubricating oils containing nanoceramics, the surface of the particles was modified with ethyl oleate. The surface modification, the ethyl oleate applied to the surface of the nanosilica, was confirmed by Fourier-transform infrared spectroscopy. Group III based lubricating oil was prepared using the surface-modified nanosilica. The particle size of the nanoparticles in the lubricating oil dispersion was examined by dynamic light scattering. Oscillating tribometer measurements were performed with different concentrations (0.1; 0.2; 0.3 wt%) of nanolubricants. Based on the tribological results, the friction coefficient of the surface-modified nanosilica is more stable, its wear is 15% lower compared to the reference. There is no significant change in the magnitude of the friction coefficient. It can be concluded that the ethyl oleate surface modification method may be suitable for tribological investigations of the acting mechanisms of nanoparticles.

Impact of surface-modified silica nanoparticle and surfactant on the stability and rheology of oil-in-water Pickering and surfactant-stabilized emulsions under high-pressure and high-temperature

Emulsions have a wide range of applications, and with the advancement in the use of nanoparticles to form stable Pickering emulsions, it is important to understand their rheological properties to infer their stability under high-pressure and high-temperature (HPHT) compared to the emulsion formed using conventional surfactants. In oil and gas production strategies, oil often forms an emulsion with brine either within reservoirs or at surface facilities in the presence of natural or artificial surfactants. Nanoparticles are also being explored to increase oil recovery from matured reservoirs. In various instances, stable emulsions are either formed in-situ (within the reservoir) or at surface facilities or injected into the reservoir to mobilize the trapped oil. It is also essential to understand their rheology for efficient oilfield application. This study investigates the impact of surface-modified silica nanoparticles (Ludox CL), NaCl salt, and surfactant on the stability of oil-in-water Pickering and surfactant-stabilized emulsions under high-pressure (0.1–10) MPa and high-temperature (303–363) K conditions. The viscosity of emulsion samples was measured at varying shear rates (0.1–1000) s−1. The viscoelastic behavior (G′, G″, η*, and δ) of the Pickering emulsion and surfactant-stabilized emulsion were also measured. The stability of the emulsions was measured in terms of changes in emulsion viscosity and droplet diameter. Both emulsions showed non-Newtonian shear thinning behavior and an increase in droplet diameter under HPHT conditions. However, the surfactant-stabilized emulsion exhibits a greater degree of change in emulsion viscosity and droplet diameter than the Pickering emulsion. It indicates that the Pickering emulsion showed better stability than the surfactant-stabilized emulsion under HPHT conditions. Hence, Pickering emulsions are an incredibly promising tool that might be employed in HPHT applications, especially for enhanced oil recovery applications, due to their better rheological stability.

Synergistic effect of microwave assisted devulcanization of waste NBR rubber and using superhydrophobic/superoleophilic silica nanoparticles on oil-water separation

In this work, waste nitrile rubber (NBR) was radio-chemo-mechanically devulcanized and used as oil/seawater separator. Pure and surface modified silica nanoparticles were applied to the new and recycled NBR compounds at different contents (i.e. 1, 2, 3, 5 and 10 wt%). The surface modification of nanoparticles was performed using triethoxyvinylsilane (TEVS) at different concentrations (i.e. 1, 5 and 10X). The rheological/mechanical properties and water/oil contact angles (WCA/OCA) of the new and recycled NBR based nanocomposites were evaluated. The results showed that using modified silica nanoparticles (at 5 wt% loading content) caused increment in the WCA from 89.89 and 95.3° to 151.56 and 153.3° and decrease in the OCA from 73.39 and 71.3° to 14.1 and 11.1° for new and recycled NBRs, respectively. It was also found that durability of sorbent against oil absorption–desorption cycles declined using the recycled rubber instead of new NBR compound (i.e. from 1000 to 700 cycles), but the oil absorption capacity enhanced (i.e. from 2.2 to 2.4 g/g). The oil separation efficiencies (OSE) of the modified nanocomposites were more than 99%. It was shown that using modified nanoparticles in RNBR caused 50% decrement in the Payne effect and 33% enhancement in the chemical/physical bonds, respectively.

A study on the synergetic effects of self/induced crystallization and nanoparticles on the mechanical properties of semi-crystalline polymer nanocomposites: experimental and analytical approaches

This work investigates the effects of nanoparticle content, aggregation/agglomeration, polymer/particle interphase, and crystallinity on the mechanical properties of high-density polyethylene (HDPE) nanocomposites. Different samples of HDPE nanocomposites, containing 0.5, 0.75, and 2 wt% of pure and surface-modified silica nanoparticles were prepared by melt-mixing method. The pure silica nanoparticles (PSN) and surface-modified silica nanoparticles with (3-aminopropyl) tri-ethoxy-silane (AMS) were characterized with field emission scanning electron microscopy (FESEM) and Fourier-transform infrared (FTIR) spectra. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to estimate the crystallinity and crystal size of the nanocomposite samples. Finally, tensile testing was performed on the nanocomposites to establish the relationship between mechanical properties and nanoparticle loading, and surface modification. The results indicate that the crystallinity and elastic modulus of the nanocomposites increased with increasing nanoparticle content. Moreover, the Gutzow–Dobreva theory was applied to approximate the degree of the induced crystallinity in each sample. A mechanical model based on two equivalent box models (EBM) was proposed to determine the crystalline, amorphous phase modulus, thickness and tensile modulus of the polymer/particle interphase region, which showed a decreasing trend with the nanoparticles content and indicated that this region was thicker for the HDPE/AMS relative to HDPE/PSN. Also, it was found that nanoparticles affected both crystalline and amorphous sections, which their effect on the crystals was more significant and presence of the well-dispersed nanoparticles in the amorphous section substantially enhanced their performance against the exerted stress.

Combined Anti-Angiogenic and Anti-Inflammatory Nanoformulation for Effective Treatment of Ocular Vascular Diseases.

Ocular vascular diseases are the major causes of visual impairment, which are characterized by retinal vascular dysfunction and robust inflammatory responses. Traditional anti-angiogenic or anti-inflammatory drugs still have limitations due to the short-acting effects. To improve the anti-angiogenic or anti-inflammatory efficiency, a dual-drug nanocomposite formulation was proposed for combined anti-angiogenic and anti-inflammatory treatment of ocular vascular diseases. CBC-MCC@hMSN(SM) complex nanoformulation was prepared by integrating conbercept (CBC, an anti-angiogenic drug) and MCC950 (MCC, an inhibitor of inflammation) into the surface-modified hollow mesoporous silica nanoparticles (hMSN(SM)). CBC-MCC@hMSN(SM) complex nanoformulation was then characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, zeta potentials, and nitrogen adsorption-desorption measurement. CBC and MCC release profile, cytotoxicity, tissue toxicity, anti-angiogenic effects, and anti-inflammatory effects of CBC-MCC@hMSN(SM) were estimated using the in vitro and in vivo experiments. CBC-MCC@hMSN(SM) complex had no obvious cytotoxicity and tissue toxicity and did not cause a detectable ocular inflammatory responses. CBC-MCC@hMSN(SM) complex was more effective than free CBC or MCC in suppressing endothelial angiogenic effects and inflammatory responses in vitro. A single intraocular injection of CBC-MCC@hMSN(SM) complex potently suppressed diabetes-induced retinal vascular dysfunction, choroidal neovascularization, and inflammatory responses for up to 6 months. Combined CBC and MCC nanoformulation provides a promising strategy for sustained suppression of pathological angiogenesis and inflammatory responses to improve the treatment outcomes of ocular vascular diseases.

Effect of alkylated surface modified silica nanoparticles on degradation products of PP during photooxidation aging: A Py-GC-MS analysis

Introducing nano-fillers to PP matrix improves its mechanical performance, but impairs the stability and changes its aging behavior. Surface modification of nano-fillers may have further influence. To investigate the effect of alkylated surface modified silica nanoparticles on PP degradation during photooxidation aging, Py-GC-MS flash evaporation technique was applied to qualitatively analyze the degradation products and quantitatively analyze their accumulation during photooxidation aging. Thermal processing of PP composites led to thermal decomposition and oxidation before aging. During photooxidation aging, both silica nanoparticles and the alkylated surface modification promoted the oxidative degradation of PP. Oxidation products accumulated, while the aging mechanism did not change. Nine typical oxidation products with different carbon numbers were selected and their accumulation during photooxidation aging were analyzed. For C1-C6 total oxidation products, there exhibits an induction period and subsequent linear accumulation during photooxidation aging. The induction period was used to show the effect of nano-silica and its surface modification. It was shortened by introducing nano-silica and further shortened by alkylated surface modification of nano-silica.

Surface-Modified Wrinkled Mesoporous Nanosilica as an Effective Adsorbent for Benzene, Toluene, Ethylbenzene, and Xylene in Indoor Air

Surfactant-extracted spherical porous silica nanoparticles with wrinkled structures were synthesized, and their adsorption performance was altered by grafting three organosilanes: n-octyltriethoxysilane, hexadecyltrimethoxysilane, and triethoxyphenylsilane onto their surface. The surface-modified silica nanoparticles were used to capture frequently detected hazardous indoor air chemicals. The physical and chemical properties of the samples were characterized using thermogravimetric analysis, Fourier transform infrared spectroscopy, N2 adsorption–desorption experiments, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. Although the organosilane surface modification did not significantly change the surface areas and pore structures of porous silica nanoparticles, the capacities of the surface-modified porous silica nanoparticles for capturing benzene, toluene, ethylbenzene, and xylene (BTEX) molecules from air were considerably higher than those of pristine porous silica nanoparticles. The dispersion forces between adsorbates and adsorbents were the primary factor that affected the absorption capacity of the surface-modified porous silica nanoparticles. Consequently, the BTEX capturing potential of surface-modified mesoporous silica featuring a long alkyl chain was high because of the relatively high dispersion force between adsorbates and the adsorbent.

Improvement of gas hydrate-based CO2 capture from CH4/CO2 mixture using silica and modified silica nanoparticles in the presence of potassium hydroxide

Separation of CO2 gas from CO2/CH4 mixture (74 mol% of CH4 and 26 mol% of CO2) was investigated, experimentally using the gas hydrate formation method in a constant-volume vessel. Silica and (3-aminopropyl) teriethoxysilane (APTES) surface-modified silica nanoparticles in the presence of potassium hydroxide were employed as additives. The impacts of various parameters such as initial pressure, gas–liquid ratio, and nanoparticle concentration were studied on gas consumption, separation factor, and recovery factor of CO2 gas in the separation process. Experiments were performed at 277.15 K and two initial pressures of 3.0 and 4.0 MPa. The presence of silica had a positive effect on gas consumption, separation, and recovery factors. The optimum results are obtained for the nanofluids including silica and potassium hydroxide, which at best case improved the gas consumption, separation factor, and recovery factor by 36 %, 29 % and 38 % compared to the pure water, respectively. The optimum nanoparticle concentration was obtained to be 0.1 wt% Besides, as the gas–liquid ratio increased, the gas consumption value raised. However, the relative amount of gas consumption and the recovery factor decreased. While the gas consumption was a direct function of the initial pressure, the separation and recovery factors were inverse functions of that.

Adsorption Dynamics of Surface-Modified Silica Nanoparticles at Solid-Liquid Interfaces.

Understanding the adsorption dynamics of nanoparticles at solid-liquid interfaces is of paramount importance to engineer nanoparticles for a variety of applications. The nanoparticle surface chemistry is significant for controlling the adsorption dynamics. This study aimed to experimentally examine the adsorption of surface-modified round-shaped silica nanoparticles (with an average diameter of 12 nm), grafted with hydrophobic (propyl chains) and/or hydrophilic (polyethylene glycol chains) agents, at an aqueous solution-silica interface with spherical soda-lime glass beads (diameter of 3 mm) being used as adsorbents. While no measurable adsorption was observed for solely hydrophobic or hydrophilic nanoparticles, a considerable level of adsorption was detected for nanoparticles comprising both hydrophobic and hydrophilic agents. Various kinetic models were employed to model the adsorption dynamics of the responsive nanoparticles. The results demonstrated that the mixed diffusion-kinetics models could predict the dynamics better than the adsorption diffusion models, indicating that the dynamics is controlled by a combination of liquid film diffusion, intra-particle diffusion, and mass action. Additionally, the adsorption of the surface-modified silica nanoparticles onto a mineral silica surface was examined using molecular dynamics simulations. The interaction energy for nanoparticles comprising both hydrophobic and hydrophilic agents was evaluated to be more favorable than that of solely hydrophobic or hydrophilic nanoparticles.

Synthesis of vinyl-based silica nanoparticles by sol–gel method and their influences on network microstructure and dynamic mechanical properties of nitrile rubber nanocomposites

Non-agglomeration and dispersion of silica nanoparticles in polymers and their interfacial interactions to polymer matrix are the most important factors that influence nanocomposites performance. In this work, vinyltriethoxysilane (VTES) as a low VOC emission coupling agent was used for surface modification of silica nanoparticles to prepare better dispersion in nitrile rubber (NBR) and improve its interfacial interactions to silica nanoparticles. The results of X-ray photoelectron spectroscopy, thermogravimetric analysis and Fourier transform infra-red spectroscopy demonstrated successful attachment of VTES molecules on the surface of silica nanoparticles. Dispersion of the modified silica nanoparticles in NBR matrix was studied using field emission scanning electron microscopy and rubber process analysis. Results demonstrated that VTES significantly improved dispersion of nanoparticles in rubbery matrix. The bound rubber content showed that VTES effectively built a bridge between the silica nanoparticles and the rubber matrix that led to promising mechanical performances and strong interfacial interactions. Effect of nanoparticle content on the mechanical performances (static/dynamic) of the NBR was evaluated. It was found that higher modulus and reinforcement indices was obtained at 3 and 5 wt% of nanoparticles. Moreover, these composites had extremely low rolling resistance, the best wet skid resistance and the lowest Heat-Build up.

Reinforcement of boron–nitrogen coordinated polyurethane elastomers with silica nanoparticles

Polyurethane elastomer nanocomposites are strategically important due to their indispensable applications in daily life and high-tech fields. Herein, a series of nanocomposites with extraordinary strength, toughness and energy dissipation are reported, which are enabled by multiple dynamic moieties including dynamic boronic ester covalent bonds, boron-nitrogen coordination bonds in the matrix and on the interface. The surface-modified silica nanoparticles with amino-silane coupling agent (D-SiO2) were added to the polyurethane matrix that contains boron-nitrogen coordination. The presence of interfacial coordination significantly improves the dispersion of D-SiO2 and enhances the interface interaction of polyurethane composites (SPU/D-SiO2), which is evidenced by scanning electron microscopy, transmission electron microscopy and rheological investigation. Through mechanical experiment analysis, these modified polyurethane composites exhibit high tensile strength and toughness. The tensile strength of SPU/10D-SiO2 increases to 19.5 ± 0.2 MPa and its tensile toughness achieves 216.9 MJ/m3, which is 35% of increase as compared with the pristine SPU that had a record-high toughness. In addition, the coordination bonds in the matrix and interface in the composites provide versatile and efficient energy dissipation during the tensile process. This work offers a facile method to improve the mechanical robustness of the newly developed supramolecular polyurethane elastomers.

Effect of the Surface Modification of Silica Nanoparticles on the Viscosity and Mechanical Properties of Silica/Epoxy Nanocomposites

ABSTRACT Silica/epoxy hybrid resin has high viscosity owing to its particle size and aggregation in the epoxy matrix, which leads to poor usability and processability. To control the size of the silica nanoparticles, surface modification of the colloidal silica (12 nm) was conducted in two steps using a silane coupling agent. The silica nanoparticles were then dispersed in the epoxy resin using an amphiphilic solvent with a high boiling point instead of mechanical dispersion. A nanosilica/epoxy hybrid resin with a low viscosity was obtained. The hybrid resin containing 3 wt% silica nanoparticles obtained a viscosity value that is 1.2% that of the neat epoxy resin. The tensile and flexural strengths of the silica/epoxy nanocomposite, as well as the impact strength of the silica/epoxy nanocomposite, were improved by plastic deformation cause by the introduction of silica nanoparticles. With silica nanoparticles loading of 10 wt%, the tensile strength of the silica/epoxy nanocomposite increased by 24%, and the impact strength increased by 112%. For higher amounts of loaded silica nanoparticles, the tensile strength of the silica/epoxy nanocomposite continuously increased, while the impact strength decreased.

Fundamental insight into the interaction between a lithium salt and an inorganic filler for ion mobility using a synergic theoretical-experimental approach

The present paper aims at providing a fundamental insight into the interaction between a lithium salt and an inorganic filler in a perspective of lithium mobility. Through a synergistic approach, coupling experimental results and molecular dynamics simulations, the influence of the surface chemical state of the nanosilica Stöber-type on the dissociation of LiTFSI and its impact on the lithium conduction properties are studied. For this purpose, the surface modification of silica nanoparticles was performed by different methods such as calcination, lithiation and capping with organosilane. The impact of the surface modification on the dissociation of the lithium salt is further investigated by electrochemical impedance spectroscopy after impregnation of the material with a defined amount of lithium salt. The combined experimental and in silico analyses of the results, performed for the first time on such systems, allow a detailed understanding of the interaction between the salt and the support and should prove itself useful for the future design of hybrid polymer electrolytes in new generation batteries.

One-step fabrication of superhydrophobic nanocomposite with superior anticorrosion performance

Superhydrophobic coatings having a self-cleaning ability and anticorrosion performance are desired in many industrial contexts; however, high costs and complex fabrication methods limit their application. In this study, thin anticorrosive superhydrophobic coatings were prepared by a scalable, simple, and inexpensive spraying method to protect AA2024-T3 surfaces. The two-component coatings were designed using fluoropolyurethane and varying concentrations of surface modified silica nanoparticles. Surface characterization was performed using contact angle and contact angle hysteresis measurements, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrum (EDS), and atomic force microscopy (AFM) techniques. Corrosion protection, water uptake, and adhesion strength of the coatings were evaluated by electrochemical impedance spectroscopy (EIS) and cross-cut tests, respectively. Increased silica nanoparticle concentrations up to 10 wt% led to increased contact angles from 92° to 167°. The lowest contact angle hysteresis was obtained for the coating containing 4 wt% nanoparticles. FE-SEM images showed that high concentrations of nanoparticles (more than 4 wt%) led to cracks in the coating surface. The best performance of a coating was observed when the coating contained 4 wt% nanosilica particles, resulting in a 164° water contact angle, almost 60 days of surface protection, an impedance value of 2.2 × 109 Ω·cm2, 0.9% water uptake, and marked adhesion strength. The impedance value of the coating with 4 wt% nanosilica particles was about 25× that of the blank sample.