Nanosilica

Herein, we report a novel nanosilica-based shear-thickening fluid, whose shear-thickening performance has been largely augmented by surface functionalizing silica employing silane chains. The functionalized shear-thickening colloids were transparent; this suggested that they have promise for application. An enhancement in viscosity was observed by over an order of magnitude by the usage of functionalized particles, which could be explained on the basis of enhanced hydroclustering and an order-to-disorder transition of the particles due to physical bonding of the silane with the base polymer...

This research aims to combine the effects of nanosilica and glass powder on the properties of self-compacting mortar at normal and at higher temperatures. The fine aggregate was replaced by waste glass powder at various percentage levels of 10%, 20%, 30%, 40% and 50%. The mechanical properties of self-compacting glass mortar (SGCM) were studied at elevated temperatures of 200, 400, 600 and 800 °C. Furthermore the effect of sudden and gradual cooling technique on the residual strength of glass mortar was also investigated In order to enhance the behavior of SCGM the nanosilica of 3% by weight of cement was added...

Silica nanoparticles (SiNPs) of different sizes were synthesized using different concentration of precursor material tetraethylorthosilicate (TEOS). The structural and morphological details of the material were obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM study was followed by energy dispersive spectroscopic analysis (EDS) for elemental analysis of the sample. The particle sizes were determined by dynamic light scattering (DLS) method. Ion exchange capacity was measured for different metal ions with sizes of the SiNPs and size-dependent ion exchange property of the material was investigated thoroughly...

Disperse polymethylsiloxane (PMS) alone and in a mixture with highly disperse nanosilica A-300 was studied as a dry powder and a hydrogel located in various dispersion media (air, chloroform alone and with addition of trifluoroacetic acid) using low-temperature 1 H NMR spectroscopy, cryoporometry, thermogravimetry, nitrogen adsorption, microscopy, infrared spectroscopy, and quantum chemistry. The powders of dried PMS and PMS/A-300 can be easily rehydrated upon strong stirring with added water. The slurry properties depend on mechanical treatment features due to stronger compaction of the secondary structures with increasing mechanical loading...

Biochar adsorption has been protruded as a sustainable green and economic process for water remediation. This technology is facing high challenges in removing different pollutants, owning to the stable chemical and physical features of biochar. Therefore, a novel nanocomposite of Liquidambar styraciflua fruit biochar-crosslinked-nanosilica (BC-Gl-NSi) was synthesized and characterized (surface area = 60.754 m2  g-1 and particle size = 17.32-36.25 nm). The designed BC-Gl-NSi nanocomposite was explored for removal of uranyl ions by the batch adsorption technique under the influence of different factors including temperature, contact time, nanocomposite dosage, pH, uranyl ion concentration as well as co-existing ions...

During earthquake propagation, geologic faults lose their strength, then strengthen as slip slows and stops. Many slip-weakening mechanisms are active in the upper-mid crust, but healing is not always well-explained. Here we show that the distinct structure and rate-dependent properties of amorphous nanopowder (not silica gel) formed by grinding of quartz can cause extreme strength loss at high slip rates. We propose a weakening and related strengthening mechanism that may act throughout the quartz-bearing continental crust...

In the semiconductor industry, perfluorinated compound removal is a major concern owing to the formation of highly toxic and hazardous hydrogen fluoride (HF) as a by-product. Calcium oxide (CaO) can be considered a promising material for HF sorption reaction process. However, the easier reaction between CaO and H2 O results in the formation of Ca(OH)2 , which ultimately limits the usefulness of CaO. The objective of the research work is preparation of CaO nanoparticles on hydrophobic silica (SiO2 ) to use as a alternative solid reducing catalyst for efficient HF removal process...

Tb-doped Y2 O3 microspheres (MSs) were prepared via a homogeneous thermal degradation process at a low temperature and then coated with a nanosilica shell (Y2 O3 :Tb@SiO2 ) using a sol-gel process. The core MSs were highly crystalline and spherical with a porous surface, single cubic phase, and particle size of 100-250 nm. Transmission electron microscopy (TEM) images clearly showed the spherical shape of the as-prepared core MSs, which were fully covered with a thick and mesoporous nanosilica shell. Fourier transform infrared (FTIR) spectra displayed the well-resolved infrared absorption peaks of silica (SiO, SiOSi, etc...

Rapid evaporation of solvent from spray colloidal droplets induces directed self-assembly among the nanoparticles, eventually interlocking them into correlated granular structures. In this work, it is demonstrated that anisotropy in colloidal interparticle interaction plays a key role in governing the surface topology of spray-dried granules. Colloidal dispersion comprised of spherical nanosilica (NS) and cylindrical carbon nanotubes (CNT) was chosen as a model system in this regard. For identical polarities of the colloidal components, granules with prominent wrinkle-like modulations are obtained, which is in drastic contrast with the case of opposite polarities...

Viscoelasticity property of bitumen is closely related to the service life of bituminous pavement. This paper evaluated the impact of one of the most efficient and widely used nanomaterials in various industries called hydrophobic nanosilica on the viscoelasticity property of bitumen and asphalt mixture. In this paper, three hydrophobic nanosilica modified bitumens and asphalt mixtures were researched by conventional physical properties test, SEM test, FTIR test, DSC test, DSR test, static creep test and dynamic creep test...

The principal objective of this research work was to investigate the results of impregnating epoxy matrix-glass fibre composite laminates with nanosilica as secondary reinforcement. 0.5, 0.75, 1 and 3 wt% nanosilica was used and thereafter properties of composites were assessed through tensile, three point bending, quasi static indentation tests and dynamic mechanical analysis. Scanning electron microscope examinations were done on fracture surfaces and failure modes were analyzed. The internal failures of the composite due to quasi-static indentation were evaluated through C-Scan...

A conductometric immunoassay protocol was designed for the sensitive detection of a liver cancer biomarker, alpha-fetoprotein (AFP), in biological fluids by using enzyme-conjugated nanometer-sized enzyme-doped silica beads. Initially, urease molecules were doped into nanosilica particles by using the reverse micelle method. Thereafter, arginase-labeled anti-AFP antibodies were covalently conjugated onto the surface of the synthesized nanoparticles. The immunoreaction was carried out in a monoclonal anti-AFP capture antibody-coated microplate with a sandwich-type assay format by using bienzyme-functionalized silica nanobeads as the recognition elements...

Human serum albumin (HSA) nanoparticles emerge as promising carriers for drug delivery. Among challenges, one important issue is the design of HSA nanoparticles with a low mean size of ca. 50 nm and having a high drug payload. The original strategy developed here is to use sacrificial mesoporous nanosilica templates having a diameter close to 30 nm to drive the protein nanocapsule formation. This new approach ensures first an efficient high drug loading (ca. 30%) of Doxorubicin (DOX) in the porous silica by functionalizing silica with an aminosiloxane layer and then allows the one-step adsorption and the physical cross-linking of HSA by modifying the silica surface with isobutyramide (IBAM) groups...

The dilatancy (Shear-thickening) is a time-independent rheological behaviour exhibited by some non-Newtonian fluids. These fluids manifest a surge in the apparent viscosity with an increase in the shear rate. If these fluids are encapsulated, they can be used to manufacture high-end stab resistance inserts (Cecchini et al., 2018) [1]. In the first part of this work, a comparison between the rheological performance of different shear-thickening fluids (STFs) based on nanosilica dispersed in glycols is presented...

Cucumber mosaic virus (CMV) is a very serious hazard to vegetable production worldwide. This study is focused on evaluation of resistance stimulated by the plant growth-promoting fungus, Phoma sp. GS8-3, or nanosilica against CMV under pot and field conditions. The specific aim was to illustrate the mechanism of resistance stimulated by GS8-3 against CMV using microarray technology. Treatments with GS8-3 as well as nanosilica significantly decreased CMV severity and titer in tobacco and cucumber under pot and field conditions, respectively...

A novel phosphonate assisted fabrication dendritic fibrous nanosilica (DFNS)-based adsorbing material was successfully synthesis via organic modification with 3-aminopropyltriethoxysilane (KH550), epichlorohydrin (ECH) and phytic acid (PA) on the grounds of hard-soft-acid-base theory, in which organic phosphorous can be applied for efficient chelating uranium(VI) (U(VI)). The adsorption properties can be evaluated by setting a series parameters (pH, adsorbent dose, contact time, initial U(VI) concentration)...

It is well-known that interaction of hydrophobic powders with water is weak, and upon mixing, they typically form separated phases. Preparation of hydrophobic nanosilica AM1 with a relatively large content of bound water with no formation of separated phases was the aim of this study. Unmodified nanosilica A-300 and initial AM1 (A-300 completely hydrophobized by dimethyldichlorosilane), compacted A-300 (cA-300), and compacted AM1 (cAM1) containing 50-58 wt % of bound water were studied using low-temperature 1 H NMR spectroscopy, thermogravimetry, infrared spectroscopy, microscopy, small-angle X-ray scattering, nitrogen adsorption, and theoretical modeling...

The study reports the preparation of a composite consisting of magnetite coated with nanosilica extracted from oil palm leaves (OPL) ash as nanosupports for immobilization of Candida rugosa lipase (CRL) and its application for the synthesis of butyl butyrate. Results of immobilization parameters showed that ∼ 80% of CRL (84.5 mg) initially offered was immobilized onto the surface of the nanosupports to yield a maximum protein loading and specific activity of 67.5 ± 0.72 mg/g and 320.8 ± 0.42 U/g of support, respectively...

The development of nanomaterials in the field of biomedical has attracted much attention in the past decades. New mesoporous nanosilica (MNS) generation, called multi functionalized MNS, presents the promising applications for efficient encapsulation, controlled release, and intracellular delivery of therapeutic agents due to their unique physiochemical properties, such as large surface area and pore volume, tunable particle size, biocompatibility, and high loading capacity. In this review, we intensively discussed the multi functionalized MNSs that respond to the demand of physical stimuli (thermo, light, magnetic field, ultrasound, and electricity), chemical stimuli (pH, redox, H2 O2 ), and biological stimuli (enzyme, glucose, ATP), individual or in combination...

The frequent use of traditional copper-based microbicides has led to the growing risk of toxicity to non-target organisms in the environment. In this work, nanosilica was conjugated with copper(II) complexes of L-glutamate (or glycine) to develop novel copper-based microbicides with good microbicidal activity, systemicity and desired safety to plant, and the obtained nanosilica-L-glutamate copper complexes (Silica-Glu-Cu) and nanosilica-glycine copper complexes (Silica-Gly-Cu) were characterized and evaluated by FT-IR, SEM, TEM, and XPS...