Different Concentrations Of TiO2 Nanoparticles Research Articles

Optical properties of transparent TiO2 films by sintering anatase nanoparticles with a CO2 laser

A novel CO2 laser additive manufacturing technique is reported in this paper for depositing transparent TiO2 films on quartz substrates using anatase TiO2 nanoparticles (NPs). Single- and double-layers of TiO2 films were prepared in two stages: (i) wet deposition using the spin-coating technique, and (ii) laser-assisted both drying of the wet layer and then sintering of the dried NPs to form a film. A theoretical model is presented to select and optimize the laser processing parameters. Scanning electron microscopy (SEM) revealed that the laser heating induces necking and coalescence of TiO2 NPs without cracking the sintered films or damaging the quartz substrate. An anti-reflection coating (ARC) model is utilized to select the film material and film thickness, aiming to reduce the reflectance and enhance the transmittance at certain wavelengths. UV/Vis spectrophotometry showed transmittance above ∼90% in the visible (Vis) range. The effect of laser power on the enhancement of transmittance is presented in this paper. Different concentrations of TiO2 NPs were used to optimize the film thickness. Single layer (∼110nm thick) and double layer films of the same total thickness as the single layer were analyzed to infer the effects of interface on the transmittance of TiO2 films. The transmittance of the single layer is higher, same as that of the double layer. Therefore, the difference in the transmittance of the single- and double-layer may be due to the effect of interface. The optical properties of the anti-reflection TiO2 coating in the UV–Vis ranges were investigated. X-ray diffraction (XRD) analysis showed that the thickness affects the crystallinity of the sintered TiO2 films.

The enhanced photocatalytic performance of CPAA doping with different concentrations of Titanium oxide nanocomposite against MB dyes under simulated sunlight irradiations

The pure conjugated polyarylene azomethine (CPAA) and its nanocomposites (CPAA-TiO2) with different concentrations of TiO2 nanoparticles were successfully prepared by in-situ technique and analyzed by different advanced techniques. XRD has confirmed the structural properties and crystallinity of (CPAA) and nanocomposites. The SEM clearly shows that the (CPAA) is uniform and homogeneous, with tightly connected aggregate layers in shape. However, the amount of TiO2 in the nanocomposites greatly affects their morphology, revealing structural differences and indicating a reaction between (CPAA) and TiO2, especially at a higher concentration of 5% TiO2. A new composite of (CPAA) was introduced and the photocatalytic effect for MB was studied. The removal efficiency of (pure-CPAA) over MB dye under simulated sunlight was 62%. However, (CPAA-TiO2 1%) destroyed 90% of MB dyes. It was discovered that the low band gap of (CPAA-TiO2 1% (2.84 eV)) accelerates high electron–hole recombination, increasing photocatalytic activity.

Study of the Tribological Properties of Nano-TiO2 Additive Water-Based Lubricants in Microrolling of Ultrathin Stainless Steel Strips

Water-based nanolubricants with different concentrations of TiO2 nanoparticles were prepared and the wettability and viscosity were evaluated. The results show that the addition of TiO2 nanoparticles improves the lubrication performance during microrolling of ultrathin stainless steel foils. In addition, the viscosity decreases dramatically with the increase in the concentration of nanoparticles, which was related to the change of dispersing agent concentration. Microrolling tests were performed to explore the lubrication conditions during microrolling of ultrathin stainless-steel strips, and the results showed that the refined surface quality of the rolled strips was achieved with 3.0 wt% TiO2. The improvement in surface quality can be attributed to the synergism of the rolling effect, polishing effect, protection film, and mending effect of TiO2 nanoparticles.

Fabrication of a Potential Electrodeposited Nanocomposite for Dental Applications

In the present study, a nanocrystalline Ni-Fe matrix with reinforced TiO2 nanoparticles as a functional nanocomposite material was fabricated by pulsed current electroforming in UV-LIGA (lithography, electroplating, and molding). The influences of TiO2 nanoparticles on the Ni-Fe nanocomposite deposition were also investigated using scanning electron microscopy, transmission electron microscopy, and in vitro cytotoxicity assay. It was found that the Ni-Fe nanocomposite with 5 wt.% TiO2 nanoparticles showed a smooth surface and better dispersion property. When the Ni-Fe nanocomposite is combined with 20 wt.% TiO2, it resulted in congeries of TiO2 nanoparticles. In addition, TiO2 nanoparticles possessed better dispersion properties as performed in pulse current electrodeposition. The microstructure of the electrodeposited Ni-Fe-TiO2 nanocomposite was a FeNi3 phase containing anatase nano-TiO2. Moreover, the electrodeposited Ni-Fe-5 wt.% TiO2 nanocomposite exhibited a smooth surface and structural integrity. Cytotoxicity assay results also proved that the Ni-Fe nanocomposite with different concentrations of TiO2 nanoparticles had good biocompatibility. Therefore, the optimization of pulse current electroforming parameters was successfully applied to fabricate the Ni-Fe-TiO2 nanocomposite, and thus could be used as an endodontic file material for dental applications.

TiO2 Blended Membranes Used in Wastewater Nanofiltration Systems from Medical Sector

The study aims to investigate the influence of TiO2 nanoparticles on the permeation and retention properties of polymeric membranes used in wastewater nanofiltration systems from the medical sector. The research is focused on the influence of the TiO2 nanoparticles concentration on the membrane properties. Additives in general determine enhanced membrane properties like permeation and retention capacity. Hydrophobicityhowever, is decreasing due to the nanoparticles affinity for water and this have an important effect on the permeation properties, at the same time with the decrease in surface roughness, with an important influence on the fouling effect. Membranes with four different concentrations of TiO2 nanoparticles were studied, from 0 to 2% nanoparticles. Results showed that small percent of nanoparticles have an important impact on the permeation properties of the membranes, finding that at 2% nanoparticles the permeation decreases due to the nanoparticles aggregations which are blocking the pores.

Thin-film nanocomposite forward osmosis membrane for water desalination: synthesis, characterization and performance improvement

Abstract The major scope of this study is the fabrication and development of a substrate and polyamide rejection layer for an efficient thin-film hydrophilic composite forward osmosis (TFC-FO) membrane. Fabrication of a thin-film nanocomposite forward osmosis membrane employing interfacial polymerization and modification of substrate characteristics using titanium dioxide (TiO2) nanoparticles as additives (TFNC-FO) are studied. Characterizations of the prepared TFC-FO and TFNC-FO membranes were determined. The morphologies of cross-section, upper and bottom surfaces for the TFC-FO and TFNC-FO membranes were studied using scanning electron microscopy (SEM). Energy-dispersive X-ray (EDX) spectroscopy was used to examine the compositions of different elements for both membranes. The hydrophilicity of the prepared TFC-FO and TFNC-FO membranes was investigated using the measurement of the contact angle test. A Fourier Transform Infrared (FT-IR) spectrophotometer was used to observe the existing functional groups of the TFC-FO and TFNC-FO membranes. The thermal stability of the membrane was evaluated via thermogravimetric analysis (TGA). The overall performance of TFC-FO membranes was evaluated with and without adding TiO2 nanoparticles through different parameters, such as membrane flux, initial feed concentration, draw solution concentrations, reverse solute fluxes, membrane permeabilities, and finally, the effect of FO membrane orientations. FO membrane performance was successfully enhanced by adding different concentrations of TiO2 nanoparticles from 0.5 to 1.5 wt%. The findings indicated that an increase in the concentration from 0.5 to 1 wt% leads to a clear increase in both the porosity and hydrophilicity of the nanocomposite substrate and consequently, an increase in the water flux. However, further increasing the concentration of TiO2 nanoparticles to more than 1 wt% affects the membrane performance.

Effect of TiO2 NPs on the growth, anatomic features and biochemistry parameters of Baby sun rose (Aptenia cordifolia).

Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO2). TiO2 NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO2 nanoparticles (0, 1, 5, 10 and 20mg L-1). Treatment with TiO2 NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO2 NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20mg L-1 TiO2 NPs. The cultivation of Baby sun rose plants in environments polluted with TiO2 NPs is recommended. This study enhances the knowledge of the effect of TiO2 NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20mg L-1 TiO2 NPs can be managed by phytoremediation. Further studies are needed to investigate this plant's tolerance strategies against stress caused by TiO2 NPs and bulk TiO2 as well as the effect of other nanoparticles on plant.

Titanium Dioxide Nanoparticles and Magnetic Field Stimulate Seed Germination and Seedling Growth of Cannabis sativa L.

In order to evaluate the effect of magnetic field intensities and concentrations of TiO2 nanoparticles on seed germination and seedling growth of Cannabis sativa L., this study was conducted. The experimental treatments included magnetopriming at intensities of 0, 30, 60, and 90 mili Tesla (mT), and the second factor included nanopriming at different concentrations of TiO2 nanoparticles, including 0, 10, 50, and 100 ppm. The results showed that sowing cannabis seeds by the combined use of magnetic fields and TiO2 nanoparticles had a significant effect on most of the studied traits. The effect of magnetic field levels showed that the highest dry weight of radicle, hypocotyl and seedling, the highest percentage of germination, germination rate, germination index and germination vigor index were related to the magnetic field at the intensity of 90 mT (5.3, 7, 6.8, 54.6, 110.9, 55.4, and 31.5% increase compared to the control, respectively). The results showed that the length and dry weight of radicle, hypocotyl and seedling were affected at the concentration of 10 ppm of TiO2 nanoparticles (2.84, 0.29, and 1.63, 0.62, 20.55 and 2.37%, respectively increase compared to the control). According to the study results, the decreasing trend of hypocotyl and seedling length was observed with increasing the concentration of nanoparticles. It is suggested to use the magnetic field as a non-invasive and non-destructive growth promoter of the plant and low concentrations of TiO2 nanoparticles as a useful tool to increase seed permeability through improving morphological and physiological properties for medicinal-industrial plant cannabis.

Study on thermo-kinetic modeling of green route synthesized inorganic loading on PVDF membrane for Cr(VI) removal and its optimization

Mathematical modeling of a phase inversion membrane was studied to predict the morphology. The effect of different concentrations of TiO2 nanoparticles on the thermodynamic and kinetic properties of polyvinylidene fluoride (PVDF) membrane casting solutions was investigated. The addition of green synthesized TiO2 increases the viscosity, and a sufficient amount results in the formation of two phases. Thermodynamics enhances the demixing rate, whereas kinetics delays the demixing rate; this trade-off between thermodynamic and kinetic parameter will affect the membrane morphology. A quadratic phase diagram for PVDF/ TiO2/solvent/Water system was drawn experimentally at different concentrations of TiO2 using a new method. Synthesized membranes were characterized by the contact angle, porosity, and permeability. Surface morphologies at different compositions were also examined using High Resolution scanning electron microscope (HRSEM). At TiO2 concentration of 2 wt% in the polymer casting solution, thermodynamics parameter dominates kinetics parameter; thus, maximum porosity with enhanced permeability was achieved experimentally. The importance of thermo-kinetic parameters was further assessed using response surface optimization. The study suggested an optimum value of 2.165% of weight% TiO2 at 5.125 pH giving excellent agreement to the experimental data.

Combination therapy with TiO2 nanoparticles and cisplatin enhances chemotherapy response in murine melanoma models.

Despite recent progressions in the treatment of melanoma, the response to conventional therapies and the long-term survival in melanoma patients still remain poor. Recently, the use of nanoparticles (NPs) has been highlighted for promoting the chemotherapeutic effects of cytotoxic drugs in melanoma. The aim of this study is to mechanistically evaluate the potential of titanium dioxide (TiO2) nanoparticles (NPs) for enhancing chemotherapy effects in in vitro and in vivo models of murine melanoma. The F10 melanoma cells were exposed to different concentrations of TiO2 NPs and/or cisplatin, then cell growth, cell viability, and cell death were evaluated. In parallel, C57BL/6 syngeneic melanoma mice were treated by TiO2 NPs and/or cisplatin, and then drug responses, tumor size and mice's organs were studied pathologically. Autophagy was examined by evaluating the formation of autophagosomes and gene expression levels of autophagy markers (ATG5 and ATG6) by fluorescent microscopy and qPCR, respectively. Nontoxic concentrations of TiO2 NPs (50µg/ml) promote anti-proliferative and cytotoxic effects of cisplatin in F10 melanoma cells, which is mediated through the induction of autophagy and necrotic cell death. Whereas TiO2 NPs have no cytotoxic or metastatic effects in melanoma mice, its combination with cisplatin enhances drug responses (up to 50%), leading to higher inhibition of tumor growth compared with each monotherapy. The combination of TiO2 NP with cisplatin enhances chemotherapy response in both in vitro and in vivo melanoma models. In addition, autophagy plays an essential role during sensitizing melanoma cells to chemotherapy.

Ice rock-resembling PHB thin films doped with TiO2 NPs as photocatalyst

This study is to evaluate the performance of TiO2 as a photocatalyst for polyhydroxybutyrate (PHB) in different concentrations. Five different concentrations of TiO2 nanoparticles (0.001–0.005 wt%) have been added to PHB blend to produce modified PHB films. The conducting characterizations using FTIR, UV, SEM and optical microscope confirmed the photocatalytic activity of TiO2 on the surface of PHB films. The SEM analyses after irradiation reports show that the PHB thin films doped with different concentrations of TiO2 nanoparticles have piece of ice rock-resembling structure nature with heterogeneous surface morphology. After irradiation, the photodecomposition rate constant showed the highest value in the presence of TiO2 with concentration (0.005 wt%). Therefore, TiO2 nanoparticles, in particular high concentration (0.005 wt%), are considered as a photocatalyst for PHB films (30 μm thickness) photodegradation.

Design of new imidazole-derivative dye having donor-Π-acceptor moieties for highly efficient organic-dye-sensitized solar cells

In the present work, we have synthesised donors/acceptor substituted derivative of imidazole 4-(1-(3-chloro-4-nitrophenyl)-4,5-diphenyl-1H-imidazol-2-yl)benzoic acid (CNI) via one-pot synthetic method and has been characterized by spectroscopic methods such as 1H-NMR, IR, SEM and EDX. The photophysical properties like, solvatochromic shift and quantum yield were estimated. Energy band gap of the CNI dye was calculated in various solvents using theoretical and experimental methods. Further, photosensitization of TiO2 nanoparticles from CNI dye has been investigated using absorption, steady state and time resolved fluorescence methods. The increase in absorbance and decrease in fluorescence spectra with different concentrations of TiO2 nanoparticles confirmed the possibility of interactions between dye and TiO2 nanoparticles. Rehm-Weller relation suggests that, decrease in fluorescence of CNI dye was due to photo-induced electron transfer process and the Stern-Volmer studies suggest that, the fluorescence quenching mechanism was due to combined dynamic and static quenching process. The photo-induced electron transfer process has been used in solar energy harvesting applications by fabricating CNI dye sensitized solar cell. Photovoltaic energy conversion efficiency and fill factor of the CNI dye were found to be 1.85 % and 0.57 respectively.

Random laser action in dye-doped xerogel with inhomogeneous TiO2 nanoparticles distribution

Rhodamine 6G-doped TEOS-derived xerogels containing different concentrations of TiO2 nanoparticles with average diameter of about 350 nm were designed to study random laser action. Due to the decantation of TiO2 nanoparticles during the sol–gel process, the obtained xerogels samples exhibits an inhomogeneous TiO2 distribution, with a higher concentration at one of the sample surfaces. By pumping the samples at each of the surfaces at a time with a ps-laser at 532 nm, differences in the emission behavior were observed. The higher concentration of TiO2 in one side of the sample, which occurs during its preparation, was shown to play an important role in the random laser energy threshold and emission spectra, depending on what side of the sample the excitation takes place. The difference in the laser threshold shows that the way scatterers are volumetrically distributed can increase or decrease the pump energy required for laser action.

Tunable wicking behavior via titanium oxide embedded in polyacrylonitrile nanofiber strings of yarn

The effect(s) of TiO2 nanoparticles on the vertical wicking behavior observed in electrospun polyacrylonitrile (PAN) nanofiber strings of yarn was investigated in this study. The capillary flow was measured in composite nanofiber strings of yarn by means of the image analysis of the rise of colored liquid soaked up in the strings of yarn; the height of liquid rise was determined as a function of time. The kinetics of capillary rise follows the Lucas–Washburn’s equation. The results obtained from the experimental design showed that the rate coefficient of the capillary rise was influenced by TiO2 nanoparticles more than the twist level in nanofiber strings of yarn. For various hot-stretching ratios, the rate of capillary rise decreased with increasing the number of TiO2 nanoparticles and the level of yarn twist. This decreasing trend was more pronounced at higher levels of yarn twist. To find how capillary behavior changed with the release of nanoparticles, the wicking mechanisms were measured at different concentrations of TiO2 nanoparticles in capillary liquid. When TiO2 nanoparticles were used in capillary liquid, they immediately filled the spaces between nanofibers in yarn and the liquid could not rise any more. The present study indicated that the wicking behavior of composite nanofiber strings of yarn was tunable provided that appropriate constructive factors, that is to say, the number of TiO2 nanoparticles and the level of nanofiber yarn twist, were chosen.

Studies on photosensitization of TiO2 nanoparticles by novel 1,3,4-oxadiazoles derivatives

In the present work, photosensitization of TiO2 nanoparticles (<25 nm) from three novel 1,3,4-oxadiazole derivatives namely TTO, TBO and TMO has been investigated using steady-state absorption, steady-state fluorescence and time-resolved fluorescence methods. Increase in absorbance and broadening of the absorption spectra for all the dyes in the presence of different concentrations of TiO2 nanoparticles confirm the possibility of interactions involving dyes and nanoparticles. Fluorescence quenching has been observed for all the dyes in the presence of colloidal TiO2 nanoparticles. Analysis of the cyclic voltammetric experimental data using Rehm-Weller relation shows that, fluorescence quenching is due to electron transfer from dye to TiO2 nanoparticles and confirms the photosensitization of TiO2 nanoparticles. Theoretical studies too confirmed the electron transfer from dye to TiO2 nanoparticles Hence, we infer that dyes used in the present studies may be useful for dye-sensitized solar cell (DSSC). Further, Stern-Volmer studies suggest that, the fluorescence quenching mechanism follows dynamic process along with minor static quenching. The apparent association constant (ks) of the interaction is also calculated using Benesi-Hildebrand model.

Drought stress and TiO2 nanoparticles affect the composition of different active compounds in the Moldavian dragonhead plant

The effects of three levels of drought stress [100%, 75% and 50% field capacity (FC)] and different concentrations of TiO2 nanoparticles (0, 5, 10, 20, 30, 50, 100, and 150 ppm) were assessed on the different metabolites of Moldavian dragonhead plant, an important ornamental, medicinal and aromatic herb. Results of high-performance liquid chromatography analysis of Moldavian dragonhead extract showed that among 14 detected compounds in the chromatogram, rosmarinic acid was the most frequent and followed by chlorogenic acid, acacetin-7-O-glucoside and apigenin-7-O-glucoside. Drought stress affected some of the metabolites and the highest values of rosmarinic, chlorogenic and p-cumaric acids were recorded in the moderate drought stress (75% FC), while in the higher drought stress (50% FC) some compounds such as caffeic acid and apigenin were increased and some other including ellagitannin and gentisic were decreased. Plant dry weight was also decreased under drought stress while essential oil content was increased. Production of studied metabolites was also influenced by application of TiO2 nanoparticles. Among different concentrations of TiO2 nanoparticles, 30, 50 and 100 ppm showed to be the most effective concentrations. Although TiO2 treatment did not significantly affect plant dry weight, the essential oil content was increased by this treatment and the highest value was obtained after treatment with 30 ppm of TiO2. According to our results, both drought stress and TiO2 nanoparticle treatments are able to increase some valuable phenolic substances including rosmarinic acid and chlorogenic acid in Moldavian dragonhead plant. Altogether, drought stress at 75% FC and TiO2 nanoparticles at concentrations of 30–50 ppm can increase phenolic bioactive compounds of Moldavian balm. New findings possibly would suggest a practical application of controlled drought stress and TiO2 nanoparticles in the culture of Moldavian balm with the purpose of increasing phenolic compounds.

A Complete experimental study of oil/water interfacial properties in the presence of TiO2 nanoparticles and different ions

Previous studies on Nanoparticles (NPs) application for Enhanced Oil Recovery (EOR) methods have revealed their effective role in the rock wettability alteration, relative Interfacial Tension (IFT) and oil viscosity reduction, formation and stabilization of the emulsions, and reduced asphaltene precipitation, which are all in direct relationship with oil/water interfacial properties. This study focuses on the interfacial properties of oil/water in the presence of Titania NPs and different ions at different pressures and temperatures. For this, different concentrations of TiO2 NPs in the Formation Water (FW) were prepared to monitor the effects of NPs on the oil/water IFT, carbonate rock wettability, zeta potential, and asphaltene adsorption. The results on IFT values indicated that NPs behavior at high pressures and temperatures is completely different, as compared to the ambient conditions, and 1000 ppm NPs introduced the lowest IFT at 600 psi and 60 °C. This reduction is potentially attributed to the asphaltene adsorption at the oil/water interface by TiO2 NPs, which hinders the asphaltene deposition at the interface and in turn IFT increasing. Contact angle results revealed two distinctive behaviors for NPs at high and low concentrations. In other words, with the first interval (below the optimum concentration), an increase in NPs concentration led to a quick wettability alteration toward the water-wet condition, and with the second one (above the optimum concentration), there was an increase in contact angle with an increase in NPs concentration, which is due to the NPs stacking near the rock surface. These results were in good accordance with zeta potential measurements, in which 1000 ppm nanofluid presented the highest stability (zeta potential value of −46.9 mV). Batch adsorption experiments resulted that catalytic TiO2 NPs are capable of adsorbing asphaltene at the oil/water interface. In addition, the results on fitting experimental data to the Langmuir and Freundlich Isotherms showed that the adsorption best fitted Langmuir Isotherm and hence the adsorption type is a monolayer.

Application of Colloidal Precipitation Method Using Sodium Polymethacrylate as Dispersant for TiO2/PVDF Membrane Preparation and Its Antifouling Properties

Immobilized titanium dioxide (TiO2) nanoparticles on flat sheet polymeric membranes have been found effective for fouling reduction in recent researches. The main challenge in this field is to obtain ultrafine and stable nanodispersions. In this study, composite polyvinylidene fluoride/TiO2 (PVDF/TiO2) ultrafiltration membranes were prepared via phase inversion and colloidal precipitation method. Stable TiO2 suspensions were prepared using sodium polymethacrylate as dispersant and sonication without altering of the coagulation bath pH. The effect of different concentrations of TiO2 nanoparticles in the coagulation bath was also investigated. The membrane morphology (distribution of nanoparticles on the membrane surface) was observed by scanning electron and atomic force microscopy. Properties of the neat and the composite membranes were also characterized using energy dispersive X‐ray spectroscopy and contact angle and membrane porosity measurements. The neat and the composite membranes were further investigated in terms of bovine serum albumin rejection and flux decline in cross flow filtration experiments. The results showed that the PVDF/TiO2 composite membrane using dimethylacetamide/triethyl phosphate as solvent and 0.05 g/L of TiO2 in the coagulation bath exhibits improved antifouling properties. POLYM. ENG. SCI., 59:E422–E434, 2019. © 2018 Society of Plastics Engineers

Effect of surface treatment and titanium dioxide nanoparticles on the mechanical and morphological properties of wood flour/polypropylene nanocomposites

ABSTRACTThis paper examines the effects of titanium dioxide (TiO2) nanoparticles and surface treating natural fibres (mercerization and acetylation) on different wood flour (WF)/polypropylene (PP) nanocomposite properties. WF and PP were mixed in an internal mixer (50% weight ratio) with different concentrations of TiO2 nanoparticles (0, 1, 3, and 5 parts by weight per hundred parts of compounds (phc)) and 3 phc PP grafted maleic anhydride (PP-g-MA) to produce a wood plastic composite, using the injection moulding method. The FTIR spectra showed the intensity of the O–H bond and the formation of acetyl groups at 3445.2 and 1763.5 cm−1, respectively. The SEM results indicated that chemical treatment creates better cohesion within the polymer matrix. Also, the tensile, flexural, and impact strengths, and the moduli of the composites increased when the TiO2 nanoparticle levels were between 1 and 3 phc. All mechanical strengths decreased as the TiO2 rose above 3 phc.

Stability and rheological properties of nanofluids stabilized by SiO2 nanoparticles and SiO2-TiO2 nanocomposites for oilfield applications

SiO2 nanofluids are advanced nanomaterials in which SiO2 nanoparticles (NPs) due to high specific surface area and dispersion stability may provide promising possibilities for various applications including their use for oilfield industries. However, SiO2 NPs (being solid charged particles) tend to aggregate and form NP clusters which are subjected to prematurely settle with time thus, rendering unstable and rheologically damaged nanofluid. In this work, a nanoparticle viz., TiO2 (∼50 nm) with concentration of 0.05 and 0.1 wt% was tested as co-stabilizer to improve the stability of SiO2 nanofluid [0.5 wt% SiO2 in base of polyacrylamide (PAM), called SN nanofluid] via reducing the homoaggregation and rate of sedimentation (ROS). SN nanofluid prepared using 0.5 wt% SiO2 in the presence of different concentrations of TiO2 NPs (0.05 and 0.1 wt%), called STN nanofluids, was also analyzed by dispersion stability, SEM, EDS, DLS, UV–vis, electrical conductivity, and rheological studies. Compared to SN nanofluid (dispersion stability ≈6 weeks), STN nanofluids exhibited enhanced dispersion stability of more than 10 weeks with reduced size of NP aggregates, consistent with SEM and EDS results. Electrical conductivity and UV–vis results support that SiO2 aggregates in presence of TiO2 remain suspended for longer time than sole SiO2 aggregates as witnessed by improved absorbance and electrical conductivity. Moreover, the effect of shear deformation on rheological properties (viscosity and viscoelastic moduli) of STN nanofluids was marginal than SN nanofluid, mainly due to the presence of TiO2 NP which in presence of SiO2 collectively formed nanocomposites of SiO2-TiO2 which controlled the properties of nanofluid. The study highlighted important aspects of colloidal suspensions and is a forward step towards the use of SiO2 based nanofluid for industrial applications.