Surfactant Cetyltrimethylammonium Bromide Research Articles

Regression analysis on the stability of surfactant mixed-MoO3 nanoparticles dispersed Gossypium arboretum biodiesel

ABSTRACT The stability, physicochemical characteristics, molybdenum trioxide (MoO3) nanoparticles in Gossypium arboretum biodiesel (BD20), and deduction of the regression equation for parameters governing the stability of biodiesel are the main subjects of this study. With and without the surfactant Cetyltrimethylammonium Bromide (CTAB), MoO3 nano additions were combined with BD20 at 60, 80, and 100 ppm concentrations. A spectrophotometer that measures the samples’ absorbance and transmittance was used to examine the stability of nano fuels on days 1, 10, and 20. CTAB mixed nano samples demonstrated high stability and enhanced essential fuel qualities when compared to basic nano fuels. The fuel BD20MoO380CTAB80 (BD20+ MoO3 80 ppm+ CTAB 80 ppm) showed a decreased transmittance of 88.3% and a higher absorbance of 4.3 AU.BD20MoO380CTAB80 recorded a higher value of Cetane number of 64 and a heating value of 41,238 kJ/kg. Physicochemical properties such as Kinematic Viscosity and Relative Density recorded lower values of 4.23 cSt and 880 kg/m3. Linear regression is applied to the obtained absorbance and transmittance values.

Enhanced electrochemical properties of cobalt oxide nanoparticle electrode modified with low concentration of cationic surfactant

Metal oxides are proficient electrode materials for supercapacitors because of their physiochemical properties, especially their wide range of oxidation states that facilitate charge transfer in redox reactions and compatibility with electrolytes. Their performances can be further improved by adding surfactants, which also help with controlled synthesis, inhibit aggregation, and alter surface characteristics. The functional groups present in the surfactant molecule can undergo chemical bonding with the surface of the metal oxide, thereby modifying their surface chemistry and electronic characteristics. Recent research has focused on increasing the specific capacitance of cobalt oxide owing to its large surface area and size. The surfactants help to control the surface modification as a size-reducing agent and improve the electrochemical properties. Herein, A facile co-precipitation method is employed in synthesising cobalt oxide without cationic surfactant cetyltrimethylammonium bromide (CTAB) and with different concentrations of CTAB, followed by calcination. Herein, we compare the electrochemical properties with varying concentrations of surfactant-assisted Co3O4. The modified Co3O4 electrode with a low surfactant concentration (CO 1) exhibits a highly specific capacitance of 531F/g at 5 mV/s with a potential window of 0.7 V. The CO 1 electrode is suitable for supercapacitor devices with a specific capacitance of 296F/g at 0.8 A/g. Moreover, the asymmetric supercapacitor composed of CO1//AC demonstrated a remarkable energy density of 46.2 Wh/Kg and a robust power density of 800 W/kg. These results indicate that the hierarchical porous structure accelerates electron and ion movement, lowers charge transfer resistance, and improves hybrid electrode capacitive properties.

Cationic-Surfactant (CTAB) Assisted Preparation of 2D Graphitic Carbon Nitride (g-C3N4) Sheets Advances Supercapacitive Performance

The distinct physicochemical characteristics of metal-free graphitic carbon nitride (g-C3N4) are gaining interest in various fields, including energy storage and conversion. However, the electrochemical performance of this material is constrained, owing to its minimal surface area. Incorporating a surfactant is one of the ways to resolve the issue of surface area and therefore improve the electrochemical performance of g-C3N4. This research delves into a method aimed at improving the supercapacitive capabilities of 2D g-C3N4 sheets through the implementation of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). Electrochemical studies reveal that the CTAB-assisted g-C3N4 sheets exhibit remarkable improvements in specific capacitance, cyclic stability, and comparative rate capability in relation to pristine g-C3N4. The specific capacitance of g-C3N4 with CTAB exceeds about 28%, which gives 162. 8 F g−1. This value is 117.7 F g−1 for electrode material without CTAB at 0.5 mA cm−2. This improved electrochemical performance can be credited to the heightened surface area, improved electronic conductivity, and optimized charge transfer kinetics facilitated by the CTAB surfactant. We aim to emphasize the enhancement of the overall performance of g-C3N4-based supercapacitors for advanced energy storage systems.

Comprehensive understanding of co-producing fermentable sugar, furfural, and xylo-oligosaccharides through the pretreatment with CTAB-based deep eutectic solvent containing Brønsted and Lewis acid

The deep eutectic solvents (DESs) with additional functionalities synthesized using the cationic surfactant cetyltrimethylammonium bromide (CTAB) have gained attention due to their remarkable enzymatic enhancement capability. By combining CTAB, lactic acid, and FeCl3, a DES containing both Brønsted and Lewis acids was synthesized and the pretreatment parameters were optimized using response surface methodology. The results demonstrated the selective and efficient delignification (83.2 %) and xylan removal (76.3 %) from canola straw by CTAB:LA:Fe3+, resulting in an increased saccharification efficiency of 81.8 %. Besides, abundant furfural (3.36 g/L) and xylo-oligosaccharides (3.41 g/L) were co-produced during pretreatment, providing comprehensive insights into the efficient co-production of fermentable sugars, furfural, and xylo-oligosaccharides. A thorough analysis of mass balance and energy flow was conducted to evaluate the entire process. Then, molecular dynamics (MD) simulations and quantum chemical calculations were performed on lignocellulosic biomass models and elucidate the interactions between the biomass and CTAB:LA:Fe3+ at the molecular level through the independent gradient model (IGM), thus explaining the high removal efficiency of hemicellulose and lignin. Furthermore, the physicochemical properties of the DESs were investigated, and molecular-level insights into the mechanism of CTAB:LA:Fe3+ pretreatment of lignocellulosic biomass were proposed in conjunction with biomass characterization such as FT-IR and CLSM, as well as MD simulations.

Optimization of a Rare Earth and Aluminum Leaching Process from Weathered Crust Elution-Deposited Rare Earth Ore with Surfactant CTAB

Ammonium sulfate is typically employed as a leaching agent in the in situ leaching of weathered crust elution-deposited rare earth ore. However, it is associated with challenges such as low efficiency in mass transfer for rare earth (RE) leaching, high usage of the leaching agent, and prolonged leaching duration. To address the issues mentioned above, the surfactant cetyltrimethyl ammonium bromide (CTAB) was compounded with 2% ammonium sulfate to form a leaching agent in this paper. The effects of CTAB concentration, temperature, pH, and leaching agent flow rate on the rare earth (RE) and aluminum (Al) leaching mass transfer process from RE ore were investigated using chromatographic plate theory. The results revealed that CTAB addition improved the RE mass transfer process while moderately inhibiting the Al mass transfer efficiency. Increasing the temperature and pH of the leaching solution led to higher theoretical plate numbers for RE and Al leaching, lowered theoretical plate height (HETP), and enhanced leaching mass transfer efficiency. However, under high temperature and alkaline conditions, the mass transfer efficiency begins to decrease, indicating that high temperature and alkaline conditions are not conducive to the synergistic enhancement of RE and Al leaching by CTAB. Considering that clay minerals have good pH buffering properties, adjusting the pH of the leaching solution during rare earth ore leaching operations was deemed unnecessary. The optimal mass transfer conditions for leaching RE and Al were identified as 2% ammonium sulfate concentration, 0.00103 mol/L CTAB concentration, pH range of 5.2–5.5 for the leaching solution, 0.6 mL/min leaching solution flow rate, and room temperature. The rare earth leaching mass transfer effect could be enhanced during summer operations.

Effect of CTAB premicelle and micelle formation on Bromophenol Blue spectra

AbstractThe interactions between surfactants and dyes in aqueous solutions are essential for gaining insights into dyeing processes across various industries and for driving advancements in chemical research. This paper investigates the interaction between the anionic dye bromophenol blue (BPB) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) in aqueous solutions. It was observed that the absorbance value at the maximum absorption peak of BPB changes systematically with increasing CTAB concentration, revealing the critical premicelle concentration (cpc) and critical micelle concentration (cmc) of CTAB. Employing a micellization model and measuring the electric conductivity across different concentrations of CTAB, the micellization thermodynamic parameters of CTAB, both in the absence and presence of BPB, were determined. The findings indicate that the associative interaction between BPB and CTAB significantly influences the formation of CTAB micelles.

Surfactant-assisted synthesis of plate-like CuS particles for high-performance symmetric capacitor

In this research, plate-like CuS particles were synthesized through a hydrothermal method using cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) as surfactants. The effects of surfactant type and content on the structural, microstructural, and electrochemical properties were explored by the various characterization techniques. Single-phase CuS powders with a space group of P63/mmc were crystallized by decomposition of the copper-thioacetamide complex during hydrothermal treatment. The spherical morphology transformed into plate-like particles by adding the CTAB surfactant, while the PVP surfactant led to an agglomeration of small spherical nanoparticles. With adding the CTAB surfactant, the specific capacitance increased from 630 to 1806 Fg−1 at a current density of 1 Ag−1, while it increased up to 1575 Fg−1 for the PVP surfactant. A symmetric capacitor was assembled on the base of spherical CuS nanoparticles as the negative electrode and the platelike CuS particles as the positive electrode. The CuS//CuS capacitor exhibited comparable electrochemical performance including an energy density of 25.62 Whkg−1 and a power density of 1488 Wkg−1, respectively.

Impact of cationic surfactant-coated hydrophilic nanoparticles on polymeric solution performance in chemical enhanced oil recovery (CEOR) from a two-dimensional porous medium

This study aims to investigate the mechanisms underlying enhanced oil recovery (EOR) through chemical injection and explore the key parameters influencing these mechanisms in a two-dimensional porous medium. Distilled water, polyacrylamide (PAM), α-Al2O3 nanoparticles, and cetyltrimethylammonium bromide (CTAB) surfactant were employed for this purpose. The effects of interfacial tension (IFT), viscosity, and zeta potential measurement were also examined. The results revealed that the injection of PAM polymer increased the viscosity of the displacing fluid, and enhanced the sweep efficiency. This resulted in a 35 % increase in the oil recovery factor compared to the water injection alone. Furthermore, the introduction of alumina (α-Al2O3) nanoparticles altered the wettability and stabilized the emulsion, leading to a further increase in the oil recovery factor. In the optimal state, the oil recovery factor reached 63.2 %. Moreover, the study of various concentrations of polymer and nanoparticles illustrated that low concentrations of polymer and high concentrations of nanoparticles in the base fluid resulted in higher oil recovery factors. Furthermore, adding CTAB surfactant ended a significant reduction in IFT, with a decrease from 45.03 to 10.33 mN/m. This reduction resulted in the highest oil recovery factor of 69 %. Consequently, the highest oil recovery factor was achieved using PAM polymer at a concentration of 500 ppm, α-Al2O3 nanoparticles at a concentration of 0.1 wt%, and CTAB surfactant at a critical micelle concentration of 1 mM in the base fluid (pure water), with a constant injection flowrate of 0.1 ml/min.

PH/Ion Dual-Responsive Emulsion Via a Cationic Surfactant and Positively Charged Magnesium Hydroxide Nanosheets.

Emulsions, formed by dispersing a liquid into another immiscible one by virtue of emulsifiers, have been widely applied in commercial applications like foods, pharmaceuticals, cosmetics, and personal care, which always confront environmental and/or toxic questions due to emulsifiers' high dosage. Recently, a study on Pickering emulsions points out a solution to stable emulsions based on the costabilizing effect of colloidal particles, which focused on surface-active particles cooperating with oppositely charged ionic surfactants. Costabilized emulsions adopting a charge-similar ionic surfactant and particles were less studied. In this article, a hexane-in-water emulsion was prepared in use of a cationic surfactant cetyltrimethylammonium bromide (CTAB) with positively charged magnesium hydroxide (MH) nanosheets at low concentrations (10-5 M and 10-2 wt %, respectively). The emulsion is stable due to the synergy by CTAB and MH nanosheets, which functions in virtue of the electric repulsion by similarly charged particles, the mechanical shielding by MH nanosheets, and restrained water drainage in lamellae between droplets due to the gelation of MH nanosheets. Moreover, the emulsion is doubly switchable within emulsification/demulsification via convenient pH or ion manipulation, a mechanism based on the breakdown and rebuilding of the costabilizing synergy. Such dual-responsive emulsions show high potential for the delicate control of drug delivery, release, and biphasic biocatalysis applications.

Derivatization-free CTAB-induced fluorescence sensing strategy for determination of daptomycin in environmental, pharmaceutical, and biological samples

A simple, economical, green, and sensitive spectrofluorimetric method was developed for the determination of the cyclic lipopeptide antibiotic daptomycin (DPT). The method is based on the sensitizing effect of the cationic surfactant cetyltrimethylammonium bromide (CTAB) on the weak fluorescent signal of DPT. After excitation at 373 nm, DPT-CTAB fluoresces at a maximum intensity of 458 nm. Under the optimized conditions, the method exhibits linearity over the concentration range of 0.50–10.0 μg/mL with a detection limit down to 0.11 μg/mL. The study revealed excellent selectivity towards DPT in the presence of the co-administered drugs. The proposed method was able to determine DPT in its commercial vials, and the results were comparable to those obtained by the reported method. The high sensitivity of the developed method allowed its estimation in water and biological fluids (spiked plasma and urine samples) with high % recoveries (95.89–105.99%). DPT was successfully determined in rat plasma after intra-peritoneal administration, and the method was applied for the calculation of its pharmacokinetic parameters (Cmax, t1/2, tmax, and AUC) in rat plasma. Comparison with the reported methods reveals many benefits of the proposed spectrofluorimetric method, such as greenness, simplicity, sensitivity, and reliability. Finally, different recent assessment tools confirmed the greenness and whiteness of the proposed method.

Подбор и оптимизация методов экстракции ДНК из листьев гледичии трехколючковой (Gleditsia triacanthos L.)

Abstract. Currently, molecular genetic methods using DNA markers are increasingly used in studies of polymorphism of various populations of woody and shrubby plants. The purpose of this work was the evaluation and selection of protocols for the isolation and purification of DNA from the leaves of Gleditsia triacanthos L. for further studies using DNA labeling. Methods. Four protocols were used to isolate DNA from the leaf blade of Gleditsia triacanthos L. Anionic detergent sodium dodecyl sulfate was used in three isolation protocols for cell lysis, potassium acetate was used for purification from polysaccharides and proteins. In the fourth protocol, a cationic surfactant cetyltrimethyl ammonium bromide was used for cell lysis, the extract was purified with a mixture of chloroform-isoamyl alcohol (24 : 1). Precipitation of the isolated DNA was carried out with isopropanol. The quality of the isolated DNA was evaluated by spectrophotometry, horizontal electrophoresis and Real-time PCR with two types of primers. Results. Optimal conditions for DNA extraction from samples of Gleditsia triacanthos L. containing a large number of metabolites affecting the quality of the isolated extract were selected. By electrophoresis, it was found that both the isolation protocol with sodium dodecyl sulfate and the isolation protocol with cetyltrimethyl ammonium bromide make it possible to obtain a sufficient amount of DNA. The most purified DNA was obtained by the third protocol using sodium dodecyl sulfate and dithiotreitol and by the fourth protocol using cetyltrimethylammonium bromide. The results of PCR of the obtained samples with ITS and psbI-psbK primers indicate that a sufficient amount of product has been obtained and the reproducibility of ISSR markers. The scientific novelty of the work consists in choosing the optimal method of DNA extraction from the leaves of Gleditsia triacanthos L., which is a complex object containing a large number of potential PCR inhibitors. The protocol with sodium dodecyl sulfate and dithiotreitol made it possible to obtain DNA in the right amount and of acceptable quality.

Development of surfactant integrated polyaniline based electrode material towards supercapacitor application

Tailoring electrode material is always important for fabricating high-performance energy storage devices. Polyaniline (PANI) is one of the most-explored electrode materials due to its electroactivity, redox property, easy and cost-effective synthesis and reasonable capacitance. Herein, PANI has been integrated with surfactants (cetyltrimethylammonium bromide, dioctyl sodium sulfosuccinate, sodium lauryl sulphate, Tween-80) via chemical oxidative polymerization pathway and utilized as the electrode material for supercapacitor. Chemical nature, crystallinity and morphology of surfactant integrated PANI samples were evaluated by FTIR, UV–Visible, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques while electrochemical properties were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy studies. Among the different PANI samples, PANI integrated with cetyltrimethylammonium bromide (PMC) afforded 2.3 times higher capacitance (528 F/g) than PANI synthesized without surfactants (PM) (229 F/g). Due to the influence of CTAB, PMC displayed higher pore volume and lesser particle size as investigated by Brunauer-Emmett-Teller and dynamic light scattering analyses. Furthermore, PMC displayed two times higher electroactive surface area as compared to PM as investigated by cyclic voltammetry studies. It has been observed that the surfactant not only improved the processability of the polymer but also assisted in enhancing the capacitance of the electrode material significantly.

Multifaceted insights into the molecular interactions of tetraalkylammonium-based quaternary ammonium salts with cetyltrimethylammonium bromide: unraveling structural, thermodynamic, and antibacterial effects

Tetraalkylammonium-based quaternary ammonium ([R4N+][DHP−]; R = Ethyl, Propyl, Butyl) salts were synthesized and subjected to in-depth analysis using NMR, FTIR and TG analysis. Subsequent investigations involved examining their impact on the aggregation patterns of the cationic surfactant Cetyltrimethylammonium bromide (CTAB) through the use of conductometry, fluorescence measurements, and UV-Visible spectroscopy. To gain a deeper understanding of the colloidal behavior of CTAB, the critical micelle concentration (cmc) of the surfactant was determined, both in the absence and presence of the quaternary ammonium salts. The observed variations in cmc values were attributed to structural changes within the surfactant-water mixture, made by the presence of these additives. In addition, the investigations include thermodynamic analysis, with a focus on studying the dependence of the cmc on temperature. The resultant thermodynamic parameters were utilized to elucidate the contributions of [R4N+][DHP−], to the electrostatic and hydrophobic interactions involved in the formation of surfactant micellar aggregates. Furthermore, the study assessed the impact of [R4N+][DHP−], on the surfactant’s antibacterial activity by quantifying the zone of inhibition, against both gram-positive and gram-negative bacterial species.

Interaction of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine drug in aqueous solution: Conductometric and molecular dynamics studies

In the present work, the interaction of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine drug in aqueous solutions was studied using conductometric measurements and molecular dynamic simulation. Conductometric data were used to determine the critical micelle concentration (CMC) values of surfactants on various amantadine aqueous solutions at T= (300.2, 310.2 and 320.2) K and 0.1 MPa. The effect of amantadine concentration (m = 0.0005, 0.0010, 0.0015 and 0.002 mol.kg−1) on CMC of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants was investigated. It was observed the CMC value of sodium dodecyl sulfate surfactant increases with increasing of amantadine concentration whereas the CMC values of cetyl trimethyl ammonium bromide surfactant decrease with increasing of amantadine concentration at the same temperature. Then, the thermodynamic properties such as standard Gibbs free energy, enthalpy, and entropy for micellization in aqueous solutions were determined. In addition, molecular dynamic simulation was carried out to understand the interaction sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine at the molecular level and microscopic interactions. The root-mean-square deviations and electrostatic, hydrogen binding and hydrophobic interactions were determined by MD simulations. It was seen, the electrostatic and hydrogen bonding interactions play a crucial role in sodium dodecyl sulfate and amantadine aqueous system. The obtained results showed the simulation and experimental data are in agreement with each other.

A multi-wavelength cross-reactive fluorescent sensor ensemble for fingerprinting flavonoids in serum and urine

Flavonoids are a kind of natural polyphenols which are closely related to human health, and the identification of flavonoids with similar structures is an important but difficult issue. We herein easily constructed a powerful fluorescent sensor ensemble by using surfactant cetyltrimethylammoniumbromide (CTAB) encapsulating two commercially available fluorescent probes (F1 and F2) with multi-wavelength emission. Fluorescence measurements illustrate the present sensor ensemble exhibits turn-off responses to flavones and flavonols but ratiometric responses to isoflavones, owing to different FRET processes. The heat map and linear discriminant analysis (LDA) results show that this single sensor can effectively distinguish 6 flavonoids belong to three subgroups by collecting the fluorescence variation at four typical wavelengths. Moreover, it can be applied to identify different flavonoids even in biofluids like serum and urine, providing potential practical application.

Surfactant-Assisted synthesis of α-and β-Ag2WO4 modified with Sulphur, Phosphorous, and boron and their applications in wastewater elimination

The surfactant cetyltrimethylammonium bromide (CTAB) was utilized to synthesize a combination of α and β-Ag2WO4 phases, which were accordingly doped with 20 % nonmetallic moieties including phosphorous (p), boron (B), and sulphur (S) via a mild precipitation route. Through characterization tools, information was obtained on surface and elemental concentration distribution, vibration, optical, morphological, and electronic properties. These materials were used as nanoadsorbents and photocatalysts. The S doped Ag2WO4 adsorbent (SAgW) has the best removal results (98.7 %) and it follows the Freundlich model of adsorption isotherm. The kinetics of dye adsorption follow the pseudo-second-order kinetic model. It was shown to achieve removal percentages of 98.6 % for indigo carmine dye (IC) and 98.8 % for methyl red dye (MR), demonstrating that the presence of other dyes has no effect on the removal percentage. AgW (CTAB-assisted synthesis) demonstrated high photocatalytic oxidation of IC at 20 mg/L in only 40 min with first-order kinetics of 0.12 min−1, exceeding that of PAgW by 6 times.

Effectively enhancing red fluorescence strategy and bioimaging applications of carbon dots

Red-emitting carbon dots have attracted much attention because of their excellent fluorescence properties. It is of great significance to synthesize red-emitting carbon dots with high fluorescence quantum yield. Herein, by using citric acid and 1,8-diaminonaphthalene as precursors in N, N-dimethylformamide, novel carbon dots (NC-CDs) exhibiting red emission at 607 nm upon excitation at 514 nm were synthesized via a solvent-thermal approach. NC-CDs aggregated in lipid droplets of cells, and hemin quenched their fluorescence. Subsequently, cationic surfactants cetyltrimethylammonium bromide, anionic surfactants sodium dodecyl sulfate and nonionic surfactants were used to functionalize the NC-CDs. The results indicated that both ionic surfactants increased the fluorescence quantum yield and solubility of NC-CDs with extended fluorescence lifetime. This approach is applicable to a class of carbon dots that possess both carboxyl and amino groups. Additionally, these functionalized NC-CDs exhibited high recognition sensitivity towards ClO− and Cu2+ respectively except for hemin. This study provides a novel approach for the synthesis of highly red-emitting carbon dots, expanding their applications in the field of biological imaging and sensing. The findings hold significant implications for the real-time monitoring of hemin in lipid droplets. Additionally, this work offers a simple method to dramatic enhance their fluorescence quantum yield.

ВЛИЯНИЕ УЛЬТРАЗВУКА НА ИЗМЕНЕНИЕ ОБЪЕМНОЙ ДОЛИ ЖИДКОСТИ В ПЕНЕ И ЕЕ УСТОЙЧИВОСТЬ

The wave method of acting on matter has long been an area of intense scientific and technological research. Ultrasonic dispersion allows to obtain various highly dispersed, homogeneous and chemically pure suspensions of solid particles in liquids; accelerates and improves the process of obtaining emulsions; ultrasonic waves of different frequencies create conditions for obtaining the structure of the material, which is characterized by isotropy of certain properties. However, the mechanism of action on dispersed systems, namely Pickering systems, is not well understood today. In this work, a study of the variation of liquid volume fraction and stability of bulk foam and its monolayers has been carried out to determine the features and nature of the failure of this dispersed system under wave action. The dependence of foam multiplicity and stability on the concentration and nature of solid particle-stabilizers (titanium oxide, clay, Aerosil-380), as well as on the content and structure of surfactant modifiers (anionic surfactant sodium decyl sulfate, cationic surfactants hexylamine and cetyltrimethylammonium bromide) is shown. The increase in the concentration of solid particles led to an increase in the resistance of foams to ultrasonic actions. The study of changes in the multiplicity and stability of foams at changing the concentration of water repellent showed that the maximum resistance to ultrasonic impacts was observed not at the maximum concentration of surfactant, but at the concentration corresponding to the maximum contact angle of wetting of particles (540). The use of long-chain surfactant cetyltrimethylammonium bromide increased the stability of the foam layer to ultrasonic action at a lower (compared to hexylamine) degree of modification of the surface of solid particles.

Troubleshooting the influence of trace chemical impurities on nanoparticle growth kinetics via electrochemical measurements.

Reproducibility issues resulting from particle growth solutions made with cetyltrimethylammonium bromide (CTAB) surfactant from different lots and product lines in a newly developed synthesis of monometallic palladium (Pd) tetrahexahedra (THH) nanoparticles are investigated via a multi-pronged approach. Time-resolved electrochemical measurements of solution potential, variation of chemical parameters in colloidal synthesis, and correlation to electrodeposition syntheses are used together to uncover the effects of the unknown contaminants on the chemical reducing environment during nanoparticle growth. Iodide-a known impurity in commercial CTAB-is identified as one of the required components for equalizing the reducing environment across multiple CTAB sources. However, an additional component-acetone-is critical to establishing the growth kinetics necessary to enable the reproducible synthesis of THH in each of the CTAB formulations. In one CTAB variety, the powdered surfactant contains too much acetone, and drying of the as-received surfactant and re-addition of solvent is necessary for successful Pd THH synthesis. The relevance of solvent impurities to the reducing environment in aqueous nanoparticle synthesis is confirmed via electrochemical measurement approaches and solvent addition experiments. This work highlights the utility of real-time electrochemical potential measurements as a tool for benchmarking of nanoparticle syntheses and troubleshooting of reproducibility issues. The results additionally emphasize the importance of considering organic solvent impurities in powdered commercial reagents as a possible shape-determining factor during shaped nanomaterials synthesis.

Effect of the cationic surfactant cetyltrimethylammonium bromide on the decomposition of ethylbenzene hydroperoxide

Effect of the cationic surfactant cetyltrimethylammonium bromide on the decomposition of ethylbenzene hydroperoxide