scholarly journals Characterization and Nanofluid Stability of CoFe2O4-APTES and CoFe2O4-PVA Nanoparticles

2020 ◽  
Vol 78 (1) ◽  
pp. 79-87
Author(s):  
Anis Arisa Roslan ◽  
Hasnah Mohd Zaid ◽  
Siti Nur Azella Zaine ◽  
Mursyidah Umar ◽  
Beh Hoe Guan
Keyword(s):  
Surface Modification ◽  
Zeta Potential ◽  
Performance Studies ◽  
Colloidal Stability ◽  
Amino Silane ◽  
Cobalt Iron Oxide ◽  
One Step ◽  
The Stability ◽  
Surface Modified ◽  
Surface Modified Nanoparticles

Nanofluid contains nanoparticles that enhanced the property of the base fluid. However, the separating layer between the nanoparticles and base fluids may interfere the nanofluids performance. Studies have been made that surface modification of nanoparticles may improve the dispersion of nanoparticles in base fluids. This paper reports the study of the colloidal stability of surface modified nanoparticles using a polymer and an amino-silane. The nanoparticles were prepared by one-step and two-step methods using cobalt iron oxide nanoparticles with brine solution and deionized water as the base fluids. Functionalization by surface modification of the nanoparticles to enhance the nanofluids stability was carried out using (3-aminopropyl) triethoxysilane (APTES) and polyvinyl alcohol (PVA). Characterization using Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscope (FESEM) and X-ray Powder Diffraction (XRD) were performed to study the functionality and morphology of the synthesized nanoparticles. The extra IR peaks such as Si-O-Si at 1063 cm-1 for CoFe2O4-APTES and C=O at 1742 cm-1 for CoFe2O4-PVA showed that there are additional elements in the cobalt ferrite due to functionalization. The size of synthesized CoFe2O4-APTES ranged between 15.99 nm to 26.89 nm while CoFe2O4-PVA is from 25.70 nm to 54.16 nm. The stability of the nanofluid were determined via zeta potential measurements. CoFe2O4-APTES nanofluid has zeta potential of -35.7 mV compared to CoFe2O4-PVA at -15.5 mV.

Preparation and Tribological Properties of Modified Field’s Alloy Nanoparticles as Additives in Liquid Poly-alfa-olefin Solution

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Chaoming Wang ◽  
Xinran Zhang ◽  
Wenbing Jia ◽  
Qiaoyuan Deng ◽  
Yongxiang Leng
Keyword(s):  
Zeta Potential ◽  
Tribological Properties ◽  
Alloy Nanoparticles ◽  
Wear Scar Diameter ◽  
Transmission Electron ◽  
Wear And Friction ◽  
One Step ◽  
Size And Morphology ◽  
Surface Modified ◽  
Surface Modified Nanoparticles

This study described the synthesis and the tribological properties of surface-modified Field’s alloy nanoparticles, which were prepared by a facile one-step nanoemulsion method and using ethyl carbamate as a surfactant, as additives in liquid poly-alfa-olefin (PAO) oil. The size and morphology of nanoparticles were investigated by transmission electron microscopy (TEM). The zeta potential, viscosity, and stability properties of the surface-modified nanoparticles suspended in PAO oil (called nanofluid) with different mass concentrations were measured by a viscometer and Zeta potential analyzer, respectively. The tribological properties of the nanofluid were tested by a ball to disk wear and friction machine. Compared with pure PAO oil, the results showed that the nanofluids had better lubricating behaviors. When the mass concentration of modified nanoparticles was 0.08 wt. %, both the friction coefficient and the wear scar diameter were the lowest.

Thin Films of Europium (III) Doped-TiO2 Prepared by Electrophoretic Deposition from Nanoparticulate Sols

2012 ◽  
Vol 507 ◽  
pp. 73-77 ◽  
Author(s):  
Mario Borlaf ◽  
Maria Teresa Colomer ◽  
Howard Titzel ◽  
James H. Dickerson ◽  
Rodrigo Moreno
Keyword(s):  
Thin Films ◽  
Zeta Potential ◽  
Electrophoretic Deposition ◽  
Colloidal Stability ◽  
Sol Gel ◽  
Complete Characterization ◽  
Constant Current ◽  
Molar Ratio ◽  
Versatile Technique ◽  
The Stability

Colloidal sol-gel is a common method used for the preparation of stable and homogeneous sols and thin films. The nanoparticulate sols can be easily deposited by EPD, which is a versatile technique for producing denser and thicker coatings than those produced by other techniques like dipping. A complete characterization of the sols, such as colloidal stability and electrophoretic mobility, which can be determined through zeta potential measurements, as well as the influence of deflocculants in the surface properties, is needed before using electrophoretic deposition. In this work, we have prepared sols of TiO2with an alkoxide:water molar ratio of 50:1 and Eu (III) doped-TiO2(2 mole % Eu (III)) using as precursors titanium (IV) isopropoxide and europium (III) acetate hydrate, respectively. The stability of the particulate sols was studied in terms of conductivity, zeta potential and viscosity evolution. Anatase stable sols, after peptization and without the use of any additive, were deposited on stainless steel substrates by electrophoretic deposition under both constant current and constant voltage conditions. Using different intensities and deposition times we have obtained thin films with different features (thicknesses and morphology) and different optical properties. The presence of europium (III) increases particle size, viscosity and peptization time and decreases the band gap of TiO2.

Performance studies of PEI/SPEI blend ultra-filtration membranes via surface modification using cSMM additives

RSC Advances ◽  
2015 ◽  
Vol 5 (35) ◽  
pp. 27594-27602 ◽  
Author(s):  
P. Kanagaraj ◽  
S. Neelakandan ◽  
A. Nagendran ◽  
D. Rana ◽  
T. Matsuura ◽  
...  
Keyword(s):  
Surface Modification ◽  
Performance Studies ◽  
Charged Surface ◽  
Filtration Membranes ◽  
Casting Solution ◽  
Ultra Filtration ◽  
Surface Modified ◽  
Sulfonated Poly

Sulfonated poly(ether imide) and charged surface modifying macromolecules were synthesized, characterized and blended into a casting solution of poly(ether imide) in different amounts to develop surface modified ultra-filtration membranes by means of improved hydrophilicity.

scholarly journals Nanomagnetit-bentonit vizes közegű diszperz rendszereinek zeta-potenciáljának vizsgálata

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Ákos Pintér-Móricz ◽  
Renáta Dr. Zákányiné Dr. Mészáros
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Colloidal Stability ◽  
Salt Content ◽  
Fluid Loss ◽  
Drilling Process ◽  
Hybrid Particles ◽  
The Stability ◽  
Application Fields ◽  
Drilling Muds

The stability of different type nanomaterials play an important role among recent scientific and industrial challenges, including the examination of the effect of polymers, surfactants and their mixture on surface and electric surface properties and aggregation extent of dispersed particles, which are of utmost importance. Bentonite and its composite with different nanomaterials are frequently used for instance in environmental protection for wastewater treatment, since due to their great specific surface area they have excellent sorption properties. There are several publications in the literature for the application of bentonite in drilling muds. By using them the fluid loss can be decreased during the drilling process, the filtration of the fluid can be increased, it also improves the rheological properties and the formation damage can also be mitigated. During research the investigation and the analysis of the zeta-potential of nanoparticles and their composites at different pH and salt content can be an interesting topic. During our experiments the electric surface properties of nanomagnetite synthetized in laboratory (NM), cation exchanged bentonite from Mád (Be) and the composite particles of these particles were investigated. Hybrid particles of different compositions (9:1, 7:3, 1:1, 3:7, 1:9) were analyzed at different potassium chloride concentrations (0.1 – 0.0001 M). The surface adsorption on the surface, i.e. the change in the surface charge can be traced well by analyzing the obtained zeta-potential values. The behavior of such systems was observed in the full pH interval, thus, valuable data were obtained regarding the colloidal stability. As for the stability, different requirements may emerge in practice, there are application fields where the colloidally stable system is advantageous, on the other hand, in some cases, ceasing the stabile system is the goal. Our investigations are of high importance in terms of stability and its characterization [1].

Stability of Suspensions and Emulsions Containing Illitic Clays

2016 ◽  
Vol 721 ◽  
pp. 337-342 ◽  
Author(s):  
Inga Jurgelane ◽  
Agnese Stunda-Zujeva ◽  
Liga Berzina-Cimdina
Keyword(s):  
Zeta Potential ◽  
Clay Minerals ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Safflower Oil ◽  
Iron Compounds ◽  
Oil In Water ◽  
Increasing Demand ◽  
The Stability

There are a lot of studies about colloidal stability of suspensions and emulsions containing clay minerals, but only few about illite containing clays. Due to increasing demand for eco cosmetics, research about the possibility to use natural colloidal particles (clay minerals) as stabilizers also increases. In this study illitic clays were used to investigate the stability of glycerol containing suspensions and safflower oil-in-water emulsions. Three types of clay samples were used – chemically untreated, after removal of carbonates and iron compounds. Viscosity and zeta potential of glycerol suspensions was determined. Samples with the highest viscosity were also the most stable. The removal of iron compounds significantly decreased the viscosity of suspensions and increased the zeta potential

Surface Modification of Nano-Copper and its Dispersive Behavior in Water

2008 ◽  
Vol 373-374 ◽  
pp. 670-673
Author(s):  
X.J. Wang ◽  
Dong Sheng Zhu ◽  
X.F. Li ◽  
Nan Wang
Keyword(s):  
Particle Size ◽  
Surface Modification ◽  
Zeta Potential ◽  
Cu Nanoparticles ◽  
Sodium Dodecylbenzenesulfonate ◽  
Absolute Value ◽  
Ph Values ◽  
The Absolute ◽  
The Stability ◽  
Electrostatic Repulsions

In this paper, by measurement of zeta potential and particle size the surface modification of Cu nanoparticles in water was investigated at different pH values and different concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant. The results show that the absolute value of zeta potential has very corresponding relation with particle size, and that the higher the absolute value of zeta potential and the smaller of the particle size are, the better dispersion and stability of copper nano-suspensions system is. It is also found that SDBS can significantly affect the value of zeta potential and particle size by electrostatic repulsions, which lead to the enhancement of the stability of the Cu suspensions, and the optimizing concentration for SDBS in 0.1% copper nano-suspensions is 0.07%, which have the best disperse results.

One-step preparation of surface modified electrospun microfibers as suitable supports for protein immobilization

2017 ◽  
Vol 8 (11) ◽  
pp. 1790-1796 ◽  
Author(s):  
Guillaume Martrou ◽  
Marc Léonetti ◽  
Didier Gigmes ◽  
Thomas Trimaille
Keyword(s):  
Protein Immobilization ◽  
Immobilized Enzymes ◽  
Step Process ◽  
One Step ◽  
The Stability ◽  
Surface Modified

Surface modified microfibers were prepared in a one-step process, and were prone to retain the activity and improve the stability of immobilized enzymes.

Surface Modification and Structure Control for Nano- and Fine-Particle Aggregation and Adhesion Behaviour Control in Liquid Phase

2014 ◽  
pp. 281-305
Author(s):  
Hidehiro Kamiya
Keyword(s):  
Surface Modification ◽  
Nanoparticle Synthesis ◽  
Surface Interaction ◽  
Structure Design ◽  
Structure Control ◽  
Post Synthesis ◽  
Surface Modified ◽  
Surface Modified Nanoparticles ◽  
The Relationship

Two kinds of approaches for preparing surface-modified nanoparticles, such as post-synthesis surface modification and in-situ surface modification, are introduced in this chapter. Post-synthesis surface modification involves the surface modification of manufactured nanoparticles. The in-situ process involves surface modification during the nanoparticle synthesis. For a non-DLVO-type surface interaction, such as a steric or bridge force, a colloid probe Atomic Force Microscope (AFM) is useful for analysing the dispersion behaviour of the nanoparticles. Some examples of the relationship between the surface interaction and the dispersion behaviour of nanoparticles are introduced to develop the interface structure design.

scholarly journals Effect of Tris and acetic acid on the stability of titania nanoparticles in different alcohols and their electrophoretic deposition process

2018 ◽  
Vol 12 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Morteza Farrokhi-Rad
Keyword(s):  
Acetic Acid ◽  
Zeta Potential ◽  
Electrophoretic Deposition ◽  
Colloidal Stability ◽  
Optimum Concentration ◽  
Titania Nanoparticles ◽  
Potential Measurement ◽  
The Stability ◽  
Kinetics Of ◽  
Titania Coating

Tris (tris(hydroxymethyl)aminomethane) was used as the dispersant to enhance the colloidal stability of titania nanoparticles in different alcohols (methanol, ethanol, isopropanol and butanol). Acetic acid (AA) was also used to increase the ionization of Tris via acid-base reaction. The effect of Tris on the stability of suspensions in the absence as well as the presence of AA was investigated by different analysis, such as conductivity and zeta potential measurement as well as FTIR analysis. It was found that Tris is protonated and adsorbed on the titania nanoparticles. It enhances their zeta potential and thus colloidal stability. The optimum concentration of Tris increased with molecular weight of alcohol (0.1, 0.2, 0.3 and 0.6 g/l for methanolic, ethanolic, isopropanolic and butanolic suspensions, respectively). The optimum concentration of Tris decreased to 0.1 g/ l for all AA containing suspensions except the methanolic ones. Titania coating was obtained by electrophoretic deposition (EPD) performed at 60 V. The current density and in-situ kinetics of deposition were recorded during EPD. It was found that the kinetics of EPD is the fastest for the suspensions with the optimum concentration of Tris (the highest zeta potential). Calcium phosphate phases were formed on the surface of titania coating after its immersion for one week in SBF at 37.5?C.

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