Influence Of Silica Nanoparticles Research Articles

Adhesion Characterization and Enhancement between Polyimide-Silica Composite and Nodulated Copper for Applications in Next-Generation Microelectronics.

As the need for high-speed electronics continues to rise rapidly, printed wiring board (PWB) requirements become ever-more demanding. A typical PWB is fabricated by bonding dielectric films such as polyimide to electrically conductive copper foil such as rolled annealed (RA) copper and is expected to become thinner, flexible, durable, and compatible with high-frequency 5G performance. Polyimide films inherently feature a higher coefficient of thermal expansion (CTE) than copper foils; this mismatch causes residual thermal stresses. To attenuate the mismatch, silica nanoparticles may be used to reduce the CTE of PI. A nodulated copper surface can be used to enhance the Cu/PI adhesion by additional bonding mechanisms that could include a type of mechanical bonding, which is a focus of this study. In this investigation, a 90° peel test was used to measure the peel strength in copper/polyimide/copper laminates containing nodulated copper and polyimide reinforced with 0, 20, and 40 wt % silica nanoparticles. The influence of silica nanoparticles on the peel strength was quantitatively evaluated. Laminates incorporating polyimide films lacking silica nanoparticles had a ∼3.75× higher peel strength compared with laminates reinforced with 40% silica. Their failure surfaces were analyzed by using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy to identify the mode of failure and to understand bonding mechanisms. The key bonding mechanism, mechanical interlocking, was achieved when the polyimide surrounded or engulfed the copper nodules when the laminate was created. Post-testing failure surface analysis revealed the presence of copper on the polyimide side and polyimide on the copper side, indicating mixed mode failure. An analytical model was developed to determine the impact of applied pressure, temperature, and time on the polyimide penetration and mechanical interlocking around the copper nodules. The model was validated by measuring the peel strength on another set of specimens fabricated using increased temperature and pressure that showed a 3× increase in peel strength compared to lower temperature/pressure processing conditions. This enhanced adhesion resulted from the lower polymer material viscosity at higher temperatures, which fosters deeper and more complete penetration around the copper nodules during processing at higher pressures for longer durations. The methodology of combining peel testing, viscosity and CTE measurement, SEM/EDX, surface chemical analysis, and penetration depth calculation developed herein enables the calculation of the desired processing parameters to enhance functionality and improve adhesion.

Comparative analysis of germination performance from several species of seeds under influence of silica nanoparticles

The first and most critical phase in growing crops is seed germination. Failure and slower germination process may have an impact on productivity. As a result, numerous strategies are needed to hasten germination and improving the quality of the seedlings. One possible strategy is the use of nanoparticles. This present study used colloidal silica nanoparticles (8 - 10 nm) with concentrations of 0 (control), 100, and 1000 mg/L. Seeds from six different species were used (Capsicum annuum, Capsicum frutescens, Cucumis sativus, Solanum melongena, Solanum lycopersicum, and Daucus carota). Seeds were germinated in dark condition for eight consecutive days. The result showed that the use of silica nanoparticles may shorten the germination time while increasing the germination index and coefficient of velocity of germination in C. annuum, C. frutescens, C. sativus, and S. lycopersicum. However, the observed effect was not very strong compared to the control. This could be due to the seeds utilized were not in dormant stage and had rather high viability. On the other hand, we found that silica nanoparticles could alter the structure of the seed coat, allowing for easier water imbibition for germination.

Influence of Silica Nanoparticles on the Properties of Nanocomposite Based on Epoxy as Concrete Protective Coating

Concrete structure especially that exposed to aggressive environment is deteriorated leading to damage of concrete buildings. Concrete coating is one of the most effective methods used for concrete protection. In this work epoxy was modified with nanosilica (NS) with different loadings. Epoxy nanosilica (EP-NS) composite was formulated and used as concrete protective coating after evaluate its properties regarding drying time, dry film thickness (DFT), adhesion strength. The coated concretes ware tested as; water absorption, contact angle (hydrophobicity) and chloride diffusion resistance by ion exchange method. Although, durability of coated concretes were examined by determining change in weight and change in compressive strength after immersion in both sulfuric acid and sodium chloride solution separately. The study revealed that, the optimum NS content is 3 % by total weight of coating. The prepared EP-NS coatings have significant protection mechanism for enhancing concrete performance against the postulated aggressive attack. Keywords: protective coating, polymer nanocomposite coating

Stability and rheological properties of foams co-stabilized by hydrophilic silica nanoparticles and amino acid/alkyl glycoside surfactants

Foams stabilized by nanoparticles (NPs) and surfactants have potential applications in the development of new environmentally friendly firefighting foams. In the present study, the mixed dispersions of anionic amino acid surfactant (SLG), nonionic alkyl glycoside surfactant (APG0810), and silica NPs were prepared. The influence of silica NPs on foamability, foam drainage, foam coarsening, and foam rheological properties of the mixture of SLG/APG0810 was systematically investigated. Results indicate that the presence of NPs results in decrease in conductivity and surface tension of the mixed dispersion. The viscosity of the mixed dispersions slightly decreases and then increases, while the foamability decreases following an increase with increasing NP concentration. The apparent viscosity of the mixed dispersions decreases over shear rate. The increase in NP concentration leads to rapid increase in viscoelastic modulus of the mixed dispersions and foams. The presence of NPs with concentration below 1 wt% results in acceleration of foam drainage and coarsening, while the presence of NPs with concentration above 1 wt% leads to deceleration of foam drainage and coarsening. This study offers theoretical support for the use of NPs in fluorine-free firefighting foams.

Silica nanofillers-reinforced polyimide composites for mechanical, thermal, and electrical insulation applications and recommendations: a review

Owing to the specific properties of polyimide, its nanocomposites have in recent years shown to be a promising polymer composite for mechanical, thermal, and electrical insulation applications. Studies have in many ways revealed the utilization of the polyimide reinforced nanofillers in the area of insulation practice be it thermal or electrical insulation. However, reinforced polyimide nanocomposites were observed to undergo interfacial bonding issues that have badly influenced their insulation behaviour during service. Dielectric properties and electrical discharge (corona discharge) resistance lifespan of polyimide composites are found degrading during long periods of exposure to elevated temperature conditions. Notwithstanding, efforts have been made on improving the electrical and thermal insulation behaviour of polyimide nanocomposites. As such, the current review study focused on the influence of silica nanoparticles on the thermal, electrical, and mechanical characteristics of polyimide matrix composites for insulation practice and applications. Thus, the vision of the authors is to contribute to the future trend of designing and processing polyimide nanocomposites for insulation applications. Thus, the authors ended the article with furtherance, challenges, and recommendations of further enhancement of polyimide nanocomposites as a candidate material for insulation (electrical and thermal). Hence, the study will pave the way for future studies.

Study on Thermal Stability of Gel Foam Co-Stabilized by Hydrophilic Silica Nanoparticles and Surfactants.

The combination of nanoparticles (NP) and surfactant has been intensively studied to improve the thermal stability and optimize the performance of foams. This study focuses on the influence of silica NPs with different concentration on the thermal stability of gel foams based on a mixture of fluorocarbon (FS-50) and hydrocarbon (APG0810) surfactants. The surface activity, conductivity, viscosity, and foaming ability of the APG0810/FS-50/NPs dispersions are characterized. The effects of NP concentration on coarsening, drainage, and decay, as well as of the gel foams under thermal action, are systematically studied. Results show that NP concentration has a significant effect on the molecular interactions of the APG0810/FS-50/NP dispersions. The surface tension and conductivity of the dispersions decrease but the viscosity increases with the increase in NP concentration. The foaming ability of APG0810/FS-50 solution is reduced by the addition of NPs and decreases with the increase in NP concentration. The coarsening, drainage, and decay of the gel foams under thermal action slow down significantly with increasing NP concentration. The thermal stability of the gel foams increases with the addition of NPs and further increases with the increase in NP concentration. This study provides a theoretical guidance for the application for gel foams containing NPs and surfactants in fire-extinguishing agents.

Silica nanoparticles acute toxicity alters ethology, neuro-stress indices, and physiological status of African catfish (Clarias gariepinus)

Silica nanoparticles (SiNPs) are a new class of nanomaterials with unique properties due to their nanoscale size. Currently, SiNPs constitute a potential value in aquaculture; nonetheless, misuse induces toxicity to fisheries and ecosystems. Hence, the present prospective is a pioneer study that illustrates the acute toxicity of SiNPs to African catfish, Clarias gariepinus (B.) and the behavioral response in a renewal static system. Moreover, the influence of SiNPs on neuro-related, stress, immune-related, and oxidative stress indices was investigated. Fish groups of average body weights (73.09 ± 2.20 g) were exposed to 96-h of various concentrations of SiNPs including 0, 50, 100, 150, 200, 250, and 300 mg L−1 without water exchange. The value of 96-h LC50 of SiNPs was computed using Finney's probit analysis. Here we show that the exposure of fish to SiNPs resulted in remarkable ethological alterations such as lethargic, surfacing, inactive, slow swimming manner, and nervousness. By increasing the SiNPs concentration, the behavior scores and mortalities reached the upper limit of top values. The comparison with the control revealed a significant dose-dependent effect by increasing in the activity of 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) with a concomitant elevation in the stress-controlled parameters (cortisol and nor-epinephrin) of all the fish groups undergone the SiNPs exposure. In contrast, there was a clear reduction in the acetylcholine esterase (AChE) level, immunological biomarkers (lysozymes and nitric oxide), and antioxidant enzymes (glutathione peroxidase (GPX) and superoxide dismutase (SOD)) of the exposed groups and the reduction elevated by increasing the SiNPs exposure concentration in comparison to the control group. Based on the study outcomes, the 96-h LC50 of SiNPs recorded 144.54 mg L−1 in C. gariepinus. We anticipate our assay to be a starting point for further applying the one-tenth of 96-h LC50- as an alternative safe treatment in therapy after considering the acute toxicity to preserve the aquaculture production and sustain human health. Additionally, it was approved that, the toxicity by the exposure to SiNPs observed clear alterations in fish behavior, neurological activity, immune and oxidative responses reflecting physiological disturbance.

Influence of silica nanoparticles on the stability of paraffin wax emulsion

Influence of silica nanoparticles on the stability of paraffin wax emulsion

Improvement of impact strength of novel intra-ply basalt/kevlar composite by addition of silica nanoparticles in comparison with basalt/kevlar composite using resin transfer mould process

The objective of this work was to enhance the impact strength of hybrid basalt/kevlar composite by the addition of 8% of silica nanoparticles. In this research work, a novel composite laminate was developed using hybrid composite fibers i.e basalt and kevlar with addition to silica nanoparticles. The influence of silica nanoparticles as filler material on the mechanical properties is studied. The two groups of materials are taken; they are the control group and the experimental group. In both groups, the basalt and kevlar fibers are used. The composite materials basalt/kevlar without addition of silica nanoparticles was considered as a control group. The composite materials basalt/kevlar with the addition of 8% silica nanoparticles was considered as an experimental group. From each group, twenty samples are taken for the study. The impact testing machine was used to conduct the impact test. The SPSS tools are used for statistical analysis. It was clearly shown that basalt and Kevlar fiber with filler exhibits an improvement of 20% increase in the impact strength when compared with basalt and Kevlar fiber without filler. The significance value of 0.029 which was less than 0.05. Within the scope of the study, the laminates with the addition of silica nanoparticles exhibit better impact strength compared with plain hybrid basalt and Kevlar composites that can be used as a replacement for automobile components and also aircraft fuselage.

The Influence of Silica Nanoparticles on the Thermal and Mechanical Properties of Crosslinked Hybrid Composites.

This paper presents the synthesis and physicochemical characterization of a new hybrid composite. Its main goals are evaluating the structure and studying the thermal and mechanical properties of the crosslinked polymeric materials based on varying chemical properties of the compounds. As an organic crosslinking monomer, bisphenol A glycerolate diacrylate (BPA.GDA) was used. Trimethoxyvinylsilane (TMVS) and N-vinyl-2-pyrrolidone (NVP) were used as comonomers and active diluents. The inorganic fraction was the silica in the form of nanoparticles (NANOSiO2). The hybrid composites were obtained by the bulk polymerization method using the UV initiator Irqacure 651 with a constant weight ratio of the tetrafunctional monomer BPA.GDA to TMVS or NVP (7:3 wt.%) and different wt.% of silica nanoparticles (0, 1, 3%). The proper course of polymerization was confirmed by the ATR/FTIR spectroscopy and SEM EDAX analysis. In the composites spectra the signals correspond to the C=O groups from NVP at 1672–1675 cm−1, and the vibrations of Si–O–C and Si–O–Si groups at 1053–1100 cm−1 from TMVS and NANOSiO2 are visible. Thermal stabilities of the obtained composites were studied by a differential scanning calorimetry DSC. Compared to NVP the samples with TMVS degraded in one stage (422.6–425.3 °C). The NVP-derived materials decomposed in three stages (three endothermic effects on the DSC curves). The addition of NANOSiO2 increases the temperature of composites maximum degradation insignificantly. Additionally, the Shore D hardness test was carried out with original metrological measurements of changes in diameter after indentation in relation to the type of material. The accuracy analysis of the obtained test results was based on a comparative analysis of graphical curves obtained from experimental tests. The values of the changes course of similarity in the examined factors, represented by those of characteristic coefficients were determined based on the Fréchet’s theory.

Influence of silica nanoparticles on running-in performance of aqueous lubricated Si3N4 ceramics

Water lubricated ceramics can achieve superlubricity following the running-in period. Nanoparticle lubricant additive is proven to significantly reduce the running-in period. However, the comprehension of the nanoparticle running-in period reduction mechanism is limited. In this paper, different types of tribology tests for Si3N4 ceramics lubricated via aqueous lubricant with nanoparticles are designed. Lubricant additives are added at different time points to ensure the effect silicon nanoparticles on running-in duration. Ceramic wear surfaces at various experimental time points are examined by the scanning electron microscope and optical microscope. The changing trend of COF during running-in period is studied. Mechanism of the surface film generation is proposed. It is found that rapid surface film generation is the essential for reducing the running-in period. Nanoparticles are depositing on the wear surface and gradually forming homogenous surface film. Ultimately, the surface film covers the wear surface and achieves dynamic balance.

Influence of silica nanoparticles on cadmium-induced cytotoxicity, oxidative stress, and apoptosis in human liver HepG2 cells.

Extensive application of amorphous silica nanoparticles (Si NPs) and ubiquitous cadmium (Cd) may increase their chances of coexposure to humans. Studies on combined effects of Si NPs and Cd in human cells are very limited. We investigated the potential mechanism of toxicity caused by coexposure of amorphous Si NPs and Cd in human liver (HepG2) cells. Results showed that Si NPs were not toxic to HepG2. However, Cd induced significant toxicity in HepG2 cells. Interestingly, we observed that a noncytotoxic concentration of Si NPs potentiated the cytotoxicity of Cd in HepG2 cells. We further noticed that coexposure of Si NPs and Cd augmented oxidative stress evidenced by the generation of oxidants (reactive oxygen species, hydrogen peroxide, and lipid peroxidation) and depletion of antioxidants (glutathione level and antioxidant enzyme activity). Coexposure of Si NPs and Cd also augmented mitochondria-mediated apoptosis in HepG2 cells indicated by altered regulation of apoptotic genes (p53, bax, bcl-2, caspase-3, and caspase-9) along with reduced mitochondrial membrane potential. Interaction data indicated that Si NPs facilitate the cellular uptake of Cd due to its strong adsorption on the surface of Si NPs. Hence, Si NPs increased the bioaccumulation and toxicity of Cd in HepG2 cells. This study warrants further research to explore the potential mechanisms of combined toxicity of Si NPs and Cd in animal models.

Porous fibers surface decorated with nanofillers: From melt‐spun PP/PVA blend fibers with silica nanoparticles

ABSTRACTBiphasic polypropylene (PP)‐polyvinyl alcohol (PVA) fibers containing silica nanoparticles with various surface hydrophobicity were melt‐spun. The localization of nanoparticles relates on the thermodynamic factors, and the design promotes a surface‐decorated fibrous scaffold with nanoparticles after selective extraction. The influence of silica nanoparticles on the melt flow index was observed, and the interface‐located Aerosil R972 silica nanoparticles lead to an increase in viscosity. The scanning electron microscopy (SEM) demonstrates the preponderant interfacial localization of Aerosil R972 nanoparticles within the biphasic fibers. The porous morphology of the obtained fibers was investigated by SEM, selective extraction experiment, X‐ray diffraction analysis, and dynamical mechanical analysis. The specific interface area of PP70‐PVA30 fibers with a draw ratio (DR) of 2 is 3.2 m2 g−1 and is further enlarged with the increase of DR. The incorporation of nanoparticles contributes to the increase of interconnectivity of the PVA phase. The further increment of DR modifies the crystalline structure, and results in better mechanical properties. The Aerosil R972‐containing fibers with the DR of 3 provide almost completely accessible PVA phase, with enough mechanical strength to be transformed into textile products, and retains a good mechanical property after selective extraction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48470.

Influence of silica nanoparticles on the functionality of water-based drilling fluids

Using nanoparticles into a drilling fluid (mud) is a promising technique that could solve a range of problems presently encountered during drilling operations. This paper reports the development of a novel drilling fluid using a biopolymer/nanoparticle mixture to improve the performance of a water-based mud (WBM) formulation, enhancing rheological, filtration and lubrication properties. The xanthan gum- SiO2 mixture developed is proposed as a solution to operating challenges in drilling operation, with the synergistic properties of nanoparticles and polymer offering desirable properties. The novel nanofluids characterised by scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy and thermal-gravimetric analysis. The modified drilling fluids were found to have higher yield point, beneficial for hole cleaning, showed less filtrate loss and more bit lubrication than conventional WBM formulations. Properly engineered, nanoparticles could improve the performance of presently deployed drilling fluids significantly.

The influence of silica nanoparticles on thermal degradation and mechanical properties of nanocomposites based on aliphatic polyurethanes

Nanocomposites based on aliphatic polyurethanes have recently attracted a lot of attention regarding economical and ecological aspects, due to their improved thermal and mechanical properties. The aim of this paper was to investigate the influence of silica nanoparticles, differing in size and specific surface, on thermal stability and degradation, lifetime and mechanical characteristics of the obtained nanocomposites. Two series of nanocomposites based on aliphatic polyurethanes were obtained by using a single-step procedure and by addition of silica nanoparticles of types A380 or N999 at different loadings (0,0 0.15, 0.5, 1,0 and 3.5 wt.%). It was found that the increase in heating rate caused shifting of the onset temperature to higher values (from 283 to 312 ?C). According to the shape of DTG curves, it was observed that the degradation mechanism of prepared nanocomposites consists of two overlapping processes, related to the scission of hard and soft building blocks. Based on DTG results, the addition of larger N999 silica nanoparticles induced lower thermal degradation, shifting the maximum rate temperatures of the first and second degradation stages to lower values, and caused the change in the degradation mechanism. Addition of smaller silica nanoparticles (A380) did not significantly affect the mechanism of the degradation reaction, indicating homogeneity of the obtained nanocomposites. The presence of A380 nanoparticles improved thermal stability of nanocomposites, by increasing the onset temperature from 286 ?C for the pristine elastomer to 303 ?C for the sample containing 3.5 wt.% of silica. Existence of interactions of A380 silica nanoparticles with hard and soft phases was observed, based on the increase in the maximum rates of the first and second degradation steps. The activation energy of thermal degradation of polyurethanes modified with A380 silica nanoparticles was obtained by using the Flyn-Wall and Toop models. Dependence of the activation energy and the lifetime of nanocomposites based on aliphatic polyurethanes on the silica content were estimated. The highest Ea values (determined for 1 and 5 % weight loss) were found for nanocomposites containing 0.5 and 0.15 wt. % of A380 silica nanoparticles (121 and 161.2 kJ/mol). A negative effect of the silica addition on mechanical properties of nanocomposites was observed. The polyurethanes containing smaller SiO2 particles (A380) had a higher tensile strength, elongation at break and hardness as compared to the elastomers filled with larger silica nanoparticles (N999).

Study on a Novel Cross-Linked Polymer Gel Strengthened with Silica Nanoparticles

This paper studied the strengthening effects of silica nanoparticles on the polyacrylamide (PAM)/hydroquinone (HQ)–hexamethylenetetramine (HMTA) composite gel. Pure PAM/HQ–HMTA gel and PAM/HQ–HMTA gels containing silica nanoparticles up to 0.3 wt % were prepared at 110 °C. Influences of silica nanoparticles on gelation performances were systematically evaluated. By the addition of silica nanoparticles, the gelation time became shorter and the gel strength was improved observably. Rheological measurements showed that silica nanoparticles enhanced both elasticity and viscosity of the gel significantly. Thermal stability of the gel was studied by differential scanning calorimetry (DSC) measurements. The maximum tolerated temperature of the gel was improved from 137.8 to 155.5 °C by the addition of silica nanoparticles with a concentration of 0.3 wt %. Furthermore, to study the strengthening mechanisms of silica nanoparticles to the gel, the microstructure and existing state of water within the gel were inves...

Influence of silica nanoparticles on corrosion resistance of sol-gel based coatings on mild steel

For this study, unfunctionalised and functionalised nanoparticles of silica (SiO2) were incorporated into a sol-gel based matrix in an effort to provide more effective corrosion protection on a mild steel substrate. Tests such as atomic force microscopy (AFM) and white light interferometry (WLI) were carried out to characterise coating microstructure and properties. Corrosion protection and coating durability was investigated using different methods which included electrochemical impedance spectroscopy (EIS) and accelerated salt spray testing to simulate a marine environment. Electrochemical test results as well as results after exposure in the neutral salt spray test indicated that the addition of silica nanoparticles led to an improvement in corrosion resistance of the coating matrix. The most effective performance was observed when the nanoparticles were functionalised. Nanoparticle functionalisation helped to avoid agglomeration during incorporation leading to a more uniform nanoparticle distribution within the coating formulation and an improvement of the coating's ability to protect against corrosion.

Reducing surfactant adsorption on rock by silica nanoparticles for enhanced oil recovery

This paper aims at making a thorough investigation on surfactant adsorption on rock under the influence of silica nanoparticles (SNP). The results showed that SNP can reduce surfactant adsorption effectively. With SNP concentration of 0.1, 0.2 and 0.3wt%, static adsorption experiments showed that sodium dodecyl sulfate (SDS) adsorption can be significantly reduced to 2.57, 2.12, and 1.73 from 2.84mg/g, and the dynamic adsorption of SDS decreased to 0.92, 0.77, and 0.66 from 1.16mg/g, respectively. Our subsequent tests conformed a 4.68% growth of oil recovery by the injection of SNP - surfactant solution compared to the normal surfactant solution. The mechanism of the enhanced oil recovery is assumed to be the inhibition of surfactant adsorption and the profile control capability of silica nanoparticles. This study proves the SNP - surfactant flooding is a cost-effective way for enhanced oil recovery.

Supramolecular system based on cylindrical micelles of anionic surfactant and silica nanoparticles

The influence of silica nanoparticles (22nm) on viscoelasticity in micellar solutions of anionic surfactant sodium oleoyl methyl taurate was investigated. It was shown that viscosity and relaxation time extremely change with increasing nanoparticle concentration in surfactant solution, and elastic modulus reaches a constant value after rising to a concentration up to 0.9wt.%. The temperature rise leads to a significant increase in the viscosity of surfactant solutions by adding nanoparticles. This fact is caused by an increase in the number of end groups in cylindrical micelles, which are able to attach to nanoparticles.

Influence of Silica Nanoparticles on Mechanical Properties of HPC

Nanotechnology proved to be a useful tool that can significantly improve the mechanical properties of ultra-high performance concrete. This paper presents the results of a long-term research which is focused on the influence of SiO2 nanoparticles on the mechanical properties of high performance concrete. Three types of HPC specimens with a weight content of 0%, 1% and respectively 3% silica nanoparticle were prepared for flexural and compressive tests. SEM analysis was done in order to understand the effect of silica nanoparticle dispersion inside the cement matrix. The aim of this paper was to investigate the nanoparticles dispersion and how it affects concrete’s mechanical properties.