Titanium Dioxide Dispersions Research Articles

Development of a microfluidic wearable electrochemical sensor for the non-invasive monitoring of oxidative stress biomarkers in human sweat

Oxidative stress is widely recognized as a pivotal factor contributing to numerous Central Nervous System (CNS) ailments. The concentrations of hydrogen peroxide (H2O2) and phosphorylated proteins within the human body serve as crucial indicators of oxidative stress. As such, the real-time monitoring of H2O2 and phosphorylated proteins in sweat is vital for the early identification, diagnosis, and management of diseases linked to oxidative stress. In this context, we present a novel microfluidic wearable electrochemical sensor by modifying the electrode with Prussian blue (PB) and loading sulfur-rich vacancy-containing molybdenum disulfide (MoS2-X) onto Multi-walled carbon nanotube (CNTs) to form coaxially layered CNTs/MoS2-X, which was then synthesized with highly dispersed titanium dioxide nanoparticles (TiO2) to synthesize CNTs/MoS2-X/TiO2 composites for the detection of human sweat H2O2 and phosphorylated proteins, respectively. This structure, with its sulfur vacancies and coaxial layering, significantly improved sensitivity of electrochemical sensors, allowing it to detect H2O2 in a range of 0.01–1 mM with a detection limit of 4.80 μM, and phosphoproteins in a range of 0.01–1 mg/mL with a threshold of 0.917 μg/mL. Furthermore, the miniature sensor demonstrates outstanding performance in detecting analytes in both simulated and real sweat. Comprehensive biosafety assessments have validated the compatibility of the electrode material, underscoring the potential of sensor as a reliable and non-invasive method for tracking biomarkers linked to CNS disorders. This microfluidic wearable electrochemical biosensor with high performance and biosafety features shows great promise for the development of cutting-edge wearable technology devices for tracking CNS disease indicators.

High stability, high solid content, low viscosity titanium dioxide dispersion

High stability, high solid content, low viscosity titanium dioxide dispersion

An experimental investigation on thermal energy storage characteristics of nanocomposite particles dispersed phase change material for solar photovoltaic module cooling

Electrical conversion efficiency of a solar photovoltaic (SPV) module suffers due to increase in its temperature. An integration of thermal energy storage system with phase change material (PCM) in a SPV module will improve its overall efficiency by maintaining its temperature. Though, Paraffin is the most common PCM for SPV cooling application, its low thermal conductivity limits its performance. Thermal performance of the Paraffin can be enhanced by utilizing high conductive nanocomposite particles. In the present research work, the enhancement in thermal characteristics of Paraffin by dispersing titanium dioxide - silver nanocomposite particles are examined. Titanium dioxide - silver nanocomposite particles (NP) are synthesized using sol-gel process and characterized using standard techniques. The effect of dispersing titanium dioxide - silver nanocomposite particles (NP) in 0.5, 1, and 1.5 % mass concentrations with thermal cycling on thermal conductivity and hence the storage performance of Paraffin are investigated. Further, the chemical, physical and thermal stabilities of nanocomposite particles dispersed Paraffin (NCDPWX) are examined. When compared to the base Paraffin, the cycled NCDPWX with 1 wt% NP exhibits a better thermal conductivity (0.384 W/mK), melting heat capacity (128 kJ/kg), freezing heat capacity (119.46 kJ/kg), melting time (6.07 min), freezing time (10.11 min), thermal stability up to 352 °C, substantial reduction in degree of super cooling (3.96 °C), impregnation ratio (102.64 %), impregnation efficiency (100.92 %), thermal storage capability (98.31 %) and better chemical stability. Overall, the synthesized NCDPWX is a suitable thermal energy storage material for cooling of SPV modules.

Instant dispersion of titanium dioxide in waterborne coatings by pinning polyacrylate nanospheres

Titanium dioxide (TiO2) with 200–400 nm diameter is an important pigment in waterborne coatings. The effective dispersion of TiO2 is a significant factor in achieving outstanding coating performance. This paper presents a novel “Instant TiO2” powder by pinning a small number of polyacrylate nanospheres (less than 5 wt%) on TiO2, which can be rapidly dispersed in water within 4 s, similar to instant coffee. The polyacrylate nanospheres copolymerized with Methyl methacrylate (MMA) and 2-Hydroxyethyl methacrylate (HEMA), are connected to the surface of TiO2 via bridge linking of silane coupling agent. This technique prevents TiO2 particles from aggregation and enables rapid dispersion of TiO2 particles in water or waterborne coating. The hydrophilic groups on HEMA facilitate the nanospheres unfolding in water to form a uniform and stable TiO2 slurry, exhibiting a significantly low viscosity (101.2 mPa·s at 200 s−1) when the concentration of TiO2 as high as 70 wt%. The “instant TiO2” denoted as TiO2-MPS-PMH shows excellent coating performance, such as impressive hiding power, and long-term storage stability under 50 °C for 28 days. Pinning polyacrylate nanospheres offers a novel approach to increase dispersion and reduce energy consumption during production in waterborne coatings by the simplified coating process. This technique also provides a potential strategy for achieving the dispersion of TiO2 in various coatings by adjusting the copolymer's components with different wettability.

Motile micro-organism based trihybrid nanofluid flow with an application of magnetic effect across a slender stretching sheet: Numerical approach

The steady magnetohydrodynamic ternary hybrid nanofluid flow over a slender surface under the effects of activation energy, Hall current, chemical reactions, and a heat source has been reported. A numerical model is developed to increase the rate of energy transfer and boost the efficiency and outcome of heat energy dissemination for a diverse range of biological applications and commercial uses. The rheological properties and thermal conductivity of the base fluids are improved by framing an accurate combination of nanoparticles (NPs). The ternary hybrid nanofluid has been prepared, in the current analysis, by the dispersion of magnesium oxide, titanium dioxide (TiO2), and cobalt ferrite (CoFe2O4) NPs in the base fluid. The physical phenomena have been expressed in the form of a system of nonlinear PDEs, which are degraded to a dimensionless system of ODEs through the similarity replacement and numerically solved by employing the MATLAB software package bvp4c. The graphical and tabular results are estimated for velocity, mass, and energy curves vs distinct physical factors. It has been noticed that the variation in the magnetic effect enhances the energy profile while the increasing number of ternary nanocomposites (MgO, TiO2, and CoFe2O4) in water lowers the energy curve. Furthermore, the effect of both Lewis and Peclet numbers weakens the motile microbe’s profile.

Effect of electrosteric stabilization of TiO2 nanoparticles on photophysical properties of organic/inorganic hybrid nanocomposite

Hybrid organic/inorganic nanocomposites are considered one of the most significant research areas due to their enhanced optoelectronic properties. This article is a detailed investigation of the effect of stabilization and dispersion of titanium dioxide (TiO2) nanoparticles on the photophysical properties of the conjugated polymer, (poly(2-methoxy-5-(2-ethylhexyloxy)1,4-phenylenevinylene (MEH-PPV). To obtain a colloidally stable nanoparticle dispersion, electrosteric stabilization of TiO2 in the MEH-PPV matrix is attempted. This work demonstrates the efficient electrostatic stabilization of TiO2 nanoparticle dispersion based on pH, zeta potential, and synthesis route. Further steric stabilization was achieved through in situ polymerization of MEH-PPV on the surface of TiO2 nanoparticles, which further reduced the van der Waal force of attraction (VFA). As a result of the combination of electrostatic and steric (electrosteric) stabilization, MEH-PPV: TiO2 hybrid nanocomposites with reduced polymer defects were successfully produced, resulting in improved absorbance, reduced non-radiative recombination rates, and long-term stability.

Long-term water sorption/solubility of two dental bonding agents containing a colloidal dispersion of titanium dioxide.

The aim was to analyze the influence of the incorporation of 4% by mass of colloidal dispersion of titanium dioxide (TiO2) nanoparticles on the long-term water sorption and solubility of two commercial universal bonding agents. In vitro studies. A colloidal dispersion of TiO2 nanoparticles was formulated and blended into two commercial dental bonding agents, i.e., Ambar Universal (FGM, Brasil) and G-Premio Bond Universal (GC, America) at 4% by mass. Forty bonding agent discs were fabricated and segregated into four bonding agent groups of 10 discs each, i.e., GA: Ambar Universal (control), GB: Ambar Universal (4% TiO2 incorporated), GC: G-Premio Bond universal (control), and GD: G-Premio Bond (4% TiO2 incorporated). The bonding agent discs were developed by dispensing the bonding agents into a silicone cast of 5 mm diameter and 1 mm depth. After bonding agent discs were desiccated, the cured discs were weighed and kept in distilled water to be evaluated for water sorption and solubility over 1 year storage period. Statistical analysis was performed by independent variable t-test performed using the IBM SPSS software (Chicago, IL: SPSS Inc). The incorporated bonding agent groups (GA and GB) showed significantly lower (P < 0.05) water sorption and solubility following 1 year of water storage in comparison to the control bonding agents. Both GC and GD demonstrated remarkably lower water sorption and solubility than GA and GB. Incorporation of the colloidal dispersion of TiO2 nanoparticles at 4% by mass into the universal bonding agents has significantly reduced their water sorption and solubility contrast to their control groups.

Anticorrosive self-stratified PDMS-epoxy coating for marine structures

Four self-stratified coatings were prepared by dispersion of titanium dioxide (TiO2) and hydrophobic fumed silica (SiO2) nanoparticles in polydimethylsiloxane (PDMS)-Epoxy mix separately and in combination. Incorporating a definite ratio of nanofillers in PDMS-Epoxy incompa ible polymer blend to form a single coat paint system with anticorrosive and improved hydrophobic properties by the self-stratifying process is the chief highlight of this research work. The appropriate characterization techniques like Fourier Transform Infrared (FTIR) spectroscopy in Attenuated Total Reflection (ATR) mode of the coatings top and bottom layers emphasized the intended stratification. The Field Emission Scanning Electron Microscopy (FESEM) displayed the morphology of the coated samples top and bottom layers and the existence of the intended stratification in the coatings cross-section. The PDMS-Epoxy coating inclusive of both the nanofillers exhibited improved hydrophobic nature, appreciable surface free energy, augmented adherence to the substrate and lesser shear force in pseudo barnacle strength test in terms of shear. This innovative formulation pertains to the application on underwater substrates with improved anti-biofouling properties.

Pt Preferential incorporation onto TiO2 IN TiO2-carbon composites for hydrogen production from glycerol photoreforming

Platinum was incorporated onto titania-mesoporous carbon composite and tested for glycerol photoreforming. The relative high surface area of the mesoporous carbon favored the good dispersion of anatase titania during sol-gel process, whereas photodeposition led to preferential incorporation of platinum onto titania. Dispersion of titania (ca. 18.4 wt%) on mesoporous carbon and subsequent photodeposition of platinum (ca. 1.3 wt%) led to the Pt/TiO2-MCH catalyst that exhibited a hydrogen production, expressed per gram of titania, three times higher than Pt/TiO2 (863 mmol /gTiO2 and 274 mmol /gTiO2, respectively, after 12 h). Reutilisation studies showed that there is a progressive loss in activity accompanied by an increase in H2/CO2 ratio. This suggests that reaction intermediates adsorbed on titania hinder light absorption and thus promotion of electrons from its conduction to the valence band (and then to platinum) which leads to a decrease in both glycerol oxidation and hydrogen production. Reduction in CO2 production is greater than that on H2, thus accounting for the observed increase in H2/CO2 ratio with reuses. A study starting from different glycerol in water concentrations (in the 0.01–10% v/v range) showed that hydrogen production rate increases with concentration up to 1% v/v, higher values mainly resulting in an increase in H2/CO2 ratio.

Stabilization and Dispersion of OSA Starch-Coated Titania Nanoparticles in Kappa-Carrageenan-Based Solution.

Titania is a white pigment used widely in papermaking, paints and cosmetic industries. Dispersion and stabilization of high concentration titania in water-based system remains a great bottleneck in industry nowadays, because aggregation of titania nanoparticles results in severe adverse effects to gloss, opacity, tint strength, color distribution and storage stability of end products. Because kappa-carrageenan (κ-CG) has excellent rheological properties such as emulsification, gelation, stability and so on, it has the ability to form gel and increase the viscosity of aqueous solution. In this work, Octenyl succinic anhydride (OSA) starch was utilized as wall material to encapsulate titania pigments using electrostatic spray drying processing. Transmission electron microscopy (TEM) showed that titania pigments were coated by OSA starch, with a final form of nanoparticle. Accelerating stability test found that around 60% OSA starch–titania particles were stably dispersed in κ-CG-based solution. All materials used in this work were natural ingredient, which would be preferred by cosmetic industry and consumers. The technique used in the present study could potentially be extended to other pigments for similar purpose.

Computational Valuation of Darcy Ternary-Hybrid Nanofluid Flow across an Extending Cylinder with Induction Effects.

The flow of an electroconductive incompressible ternary hybrid nanofluid with heat conduction in a boundary layer including metallic nanoparticles (NPs) over an extended cylindrical with magnetic induction effects is reported in this research. The ternary hybrid nanofluid has been synthesized with the dispersion of titanium dioxide, cobalt ferrite, and magnesium oxide NPs in the base fluid water. For a range of economical and biological applications, a computational model is designed to augment the mass and energy conveyance rate and promote the performance and efficiency of thermal energy propagation. The model has been written as a system of partial differential equations. Which are simplified to the system of ordinary differential equations through similarity replacements. The computing approach parametric continuation method is used to further process the resultant first order differential equations. The results are validated with the bvp4c package for accuracy and validity. The outcomes are displayed and analyzed through Figures and Tables. It has been observed that the inverse Prandtl magnetic number and a larger magnetic constant reduce the fluid flow and elevate the energy profile. The variation of ternary hybrid NPs significantly boosts the thermophysical features of the base fluid.

Comparative Studies on Dispersion Characters of Titanium Dioxide (TiO2) Nanoparticles for Rodent Toxicology Studies

This research aimed to find a suitable vehicle (media) for dispersing titanium dioxide nanoparticles (TiO2 NPs) to investigate their toxicity in laboratory rodents.The TiO2 NPs were suspended in different vehicles viz., distilled water, Tween 80 (0.1% v/v), normal saline, normal saline + Tween 80 (0.1% v/v) and carboxymethylcellulose (CMC; 0.1%, 0.2%, 0.3% or 0.4% w/v). The hydrodynamic diameters, zeta potential, and polydispersity index were measured by the dynamic light scattering (DLS) technique by employing a zeta sizer. The TiO2 NPs in Tween 80 (0.1% v/v) and CMC (0.2% w/v) showed lesser hydrodynamic diameter compared to other vehicles. Further, TiO2 NPs dispersed in CMC (0.1%, 0.2%, or 0.3% w/v) showed relatively better zeta potential in terms of better stability than other media examined. The polydispersity index of nanoparticles was relatively less for CMC: 0.1% w/v followed by CMC: 0.2% w/v. Thus, it is concluded that CMC (0.2% w/v) can be used as an ideal vehicle among the various media examined for delivery of TiO2 NPs for toxicity testing in laboratory rodents.

Implementación del proceso vía slurry y concentrado de pigmentos en fórmulas de pintura tipo látex. Desafíos y oportunidades para la planificación

Changes in product production are limited by high costs in infrastructure, procedures, reformulations and / or substitution of raw materials. Therefore, it is necessary to develop and innovate technologies that minimize impacts, without damaging product quality standards. In paint formulations, the dispersion process is of vital importance, which is why this research evaluated the possibility of implementing the technique slurry and pigment concentrate in the traditional way of manufacturing latex-type paints of the premium line (satin and exterior), and partially eliminate the dispersion stage, maintaining the physicochemical characteristics according to Venezuelan COVENIN standards. For this, three types of slurries were used; I: Aqueous dispersion of calcium carbonate (CaCO3), magnesium silicate (MgSiO3) and Kaolin (Al2Si2O5 (OH)4), II: Aqueous dispersion of CaCO3, III: Aqueous dispersion of CaCO3 and Kaolin. Likewise, in the pigment concentrates, two types of aqueous dispersion of titanium dioxide (TiO2) of medium and high dispersibility were used. As a result, there were no significant variations in terms of the quality characteristics of the paints obtained through the process by slurry and pigment concentrate with respect to the traditional manufacturing process. In addition, a reduction of 102 minutes was achieved on the global manufacturing time, since the previous dispersion of the pigments and extenders present in the pigment concentrates and slurries was used, thus eliminating one of the four stages of the manufacturing process of the lines (scattering stage). With the use of slurries and pigment concentrates, it was possible to increase productivity by 31.20 %, becoming an alternative for paint manufacturers, without investing in new equipment.

Efficient dispersion of TiO2 in water-based paint formulation using well-defined poly[oligo(ethylene oxide) methyl ether acrylate] synthesized by ICAR ATRP

In this work, a new polymeric dispersants based on poly[oligo(ethylene oxide) methyl ether acrylate] (POEOA) as hydrophilic block and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and dopamine (Dopa) as anchoring molecules, have been synthetized and successfully used as efficient tailor-made polymers for the aqueous dispersion of titanium dioxide (TiO2) particles. The controlled structure of this new class of additives was obtained by initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP). The proposed polymer dispersants were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance analysis (1H NMR). The dispersion efficiency was evaluated by dynamic light scattering (DLS), zeta potential (ζ), rheology and transmission electron microscopy (TEM). The influence of different stabilizing blocks bounded to the same anchoring block on the dispersion efficiency was evaluated in aqueous dispersions of TiO2 using a common water-based paint formulation (satin vinyl paint). Aiming for industrial validation, a satin paint was also formulated with the new dispersants. Higher gloss (up to 39%) and improved pigment dispersion were observed when using the tailor-made polymers, comparing to the use of a standard commercial poly(acrylic acid) (PAA) dispersing agent. The data presented suggest that POEOA-based macrostructures are highly efficient additives for the dispersion of TiO2 in water-based paint formulations.

Investigation of possible storage period of polymer composite material based on fl uoroplast-40

Products made of fl uoroplastics and composite materials based on them are widely used as structural components and sealing parts in the rocket and space industry. Therefore, they must have high physical and mechanical properties and operational characteristics. There is a need for long-term storage of parts before installation in units. One of the materials that can be used in extreme conditions: high temperatures, increased radiation and aggressive environments, is a composite material based on fl uoroplast-40 fi lled with a dispersed titanium dioxide. The article presents the results of a research which make it possible to guarantee the storage stability of the mechanical properties of fl uoroplast-40T in the workpieces for 30 years.

Experimental and numerical investigation of melting/solidification of nano-enhanced phase change materials in shell & tube thermal energy storage systems

In this work, the melting/solidification process of the nano-enhanced phase change materials (NePCM) was investigated experimentally and numerically using a horizontal shell & tube heat exchanger equipped with longitudinal fins. The NePCM was prepared by dispersing titanium dioxide nanoparticles (TiO2NPs) in stearic acid (SA). The effect of geometry parameters and nano particle content on melting/solidification rate of PCM were investigated. The results showed that using longitudinal fins could reduce the required time for melting and solidification by around 54% and 76%, compared to the system without fins, respectively. while the greatest effect of adding the TiO2-NPs was related to unfinned tube heat exchanger, which reduced the required time by 6% and 8% for melting and solidification, respectively. Furthermore, it was concluded that adding nanoparticles could offer its positive effect for enhancing the melting rate only while using unfinned tube heat exchanger.

Development of sedimentation resistant water-acrylic titanium dioxide dispersions

According to the results of the research, the effect of stabilization of dispersions of titanium dioxide in water-acrylic compositions was established. It was proved that in aqueous-acrylic suspensions at all variations of film-forming agent (from 0 to 5 g/dm3), the maximum of stabilizing activity of the surfactants under study is achieved at CSAS=0.25 g/dm3. The minimum deposition rate of titanium dioxide dispersions at a dosing of 0.25 g/dm3 of sodium polyacrylate was at the level of 0.097 10-3 g/s at any content of film-forming agent (Cff=0.5÷5 g/dm3) in suspensions. At the introduction of the same concentration (CSAS=0.25 g/dm3) of the polyether siloxane copolymer, a decrease in sedimentation rate to 0.053 10-3 g/s in suspensions with a limited acryl content (C≤1 g/dm3) was recorded. At an increase in the concentration of a film-forming agent (C&gt;1 g/dm3) in suspensions, sedimentation stability decreased, which is proved by an increase in the sedimentation rate of TiO2 to 0.110∙10-3 g/s at Cff=5.0 g/dm3. It was found that in aqueous-acrylic suspensions with the film-forming content from 0.5 to 1 g/dm3, the minimum average diameter was 2.64÷3.1 μm CSAS=0.25 g/dm3. Further concentration of acryl (Cff=4÷5 g/dm3) at the same dosage of polyether siloxane copolymer was accompanied by an increase in the average particle size up to 4.30÷4.61 μm. The maximum of wedging activity of sodium polyacrylate (CSAS=0.25 g/dm3) corresponds to the same minimum of the average diameter (2–3 μm).

New composite material based on Kaolinite, cement, TiO2 for efficient removal of phenol by photocatalysis

Photocatalysis is one of the most important process and was used to eliminate various organic pollutants as phenol in water. In this research study, a new composite containing Kaolinite, cement, and wood fibers modified by titanium oxide TiO2 was elaborated in order to be used in addition of building materials, as photocatalyst for the degradation of phenol. Different kinds and amounts of TiO2 (PC500, P90, and C-TiO2) were immobilized by a simple method inside the composite materials based. The matrix of the hybrid materials was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), N2 adsorption-desorption (BET), and scanning electron microscope (SEM). These investigations confirmed the dispersion of titania in the new composite materials. The FTIR result has shown that clay particles were successfully treated before their insertion in the composite, by the appearance of two peaks at 2921-2851 cm-1. The XRD results reveal the identification of crystalline phase of TiO2 as anatase. The photocatalytic activity of the composite materials was investigated towards degradation of phenol in aqueous solution under UV light irradiation (369 nm). It has been found that photocatalytic efficiency was significantly enhanced when TiO2 is added. The highest photocatalytic activity has been shown by 3% P90-comp of 41.65% in comparison with 3% PC500 and 3% C-TiO2 which are 29.88% and 22.64 %, respectively. It was shown that the experimental data of kinetic reaction are well fitted by first-order model.

Investigations on mechanical behavior of hot rolled Al7075/TiO2/Gr hybrid composites

In the present work, influence of titanium dioxide (TiO2) and graphite (Gr) hybrid reinforcement on microstructure and mechanical behavior of Al7075 alloy is studied. Al7075 and its hybrid composite samples were fabricated by using stir-casting and hot rolling technique. Hot rolling was carried out at a temperature of 450 °C with a reduction-ratio of 90%. Microstructure examination showed a good dispersion of titanium dioxide and graphite reinforcement particles with excellent bond with Al7075 matrix alloy. In case of hot rolling, both the reinforcements were found to be aligned in the direction of rolling. The microhardness and tensile strength of hybrid composites were remarkably improved in case of hot rolling compared to that of cast composites.

Optimization of a Droplet-Based Millifluidic Device to Investigate the Phase Behavior of Biopolymers, Including Viscous Conditions

Phase diagrams are widely used to map and control the assembly states of biopolymers. However, these studies are highly time and material consuming. Here, we present the optimization of a simple tool based on millifluidics to screen phase diagram of biopolymers, pure or in mixtures with other biopolymers. It is used (i) to generate a homogeneous mixture of biopolymers/buffer and/or biopolymers 1/ biopolymers 2 in a short time (~s), (ii) to vary the composition of the mixtures by adjusting the flow rates, and (iii) to determine the turbidity of the drop by grey level analysis. The mixing efficiency and the calibration turbidity vs. grey level were performed using colloidal titanium dioxide dispersions. The use of millifluidics reduced the amount of material of ten-fold and the experimentation time by a factor five compared to a conventional bulk approach. This set-up was used to explore functional synergies between proteins and polysaccharides as an example of application.