Effect Of CTAB Research Articles

Effect of CTAB on the aggregation properties of Congo Red organized in layer-by-layer electrostatic self-assembled film: a spectroscopic and Atomic force microscopy study

Effect of CTAB on the aggregation properties of Congo Red organized in layer-by-layer electrostatic self-assembled film: a spectroscopic and Atomic force microscopy study

Effect of CTAB and PVP on morphological and optical properties of CdS microstructures

Effect of CTAB and PVP on morphological and optical properties of CdS microstructures

The effect of CTAB and lactic acid as surfactants in ZnS quantum dots: a simple method for colloidal synthesis and characterization

The effect of CTAB and lactic acid as surfactants in ZnS quantum dots: a simple method for colloidal synthesis and characterization

Effect of CTAB on the Oxidation of Furfural to Maleic Acid over Hierarchical CoAPO-5 Catalysts

Effect of CTAB on the Oxidation of Furfural to Maleic Acid over Hierarchical CoAPO-5 Catalysts

CTAB decorated SnO2 nanosheet assembled micro-flowers for photocatalysts

In this work, CTAB decorated SnO2 nanosheets are synthesized by a simple hydrothermal method. The effect of CTAB on the morphology and photocatalytic performance of SnO2 micro-flowers is investigated, revealing that CTAB played a significant role in the formation of SnO2 micro-flowers. In addition, the photocatalytic performance of SnO2 nanosheet assembled microflowers is characterized through the degrading of methylene blue, erosin and rhodamine B dyes. The as-prepared SnO2 nanosheet assembled micro-flowers have exhibited superior photocatalytic activity and excellent stability, which could be contributed to the unique self-assembled micro-flower structure. This suggests that the as-synthesized SnO2 micro-flowers may have great potential for wastewater purification applications.

Effect of CTAB on the architecture and hydrophobicity of electrodeposited Cu–ZrO2 nano-cone arrays

This study explores the hydrophobicity of micro and nano-hierarchical structured Cu–10 g/L ZrO2 pulse electrodeposits as a function of different concentrations (0.1, 0.5 and 1 g/L) of cetrimonium bromide (CTAB, a cationic surfactant) addition. Beyond 0.1 g/L CTAB loading, the composite coatings display duplex nano-cone morphology. Specifically, 0.5 g/L CTAB loaded coating shows free standing hemispherical morphologies consisting of vertically aligned nano-cone arrays, whereas 1 g/L CTAB loaded coating displays flowery like hierarchical nano-cone morphology. However, 0.1 g/L CTAB addition makes the coating morphology finer as compared to non-CTAB loaded coating with ordered nano-cone morphology. Among all the developed coatings, 0.5 and 1 g/L CTAB loaded coatings display superhydrophobic behavior by mimicking the ‘lotus leaf’ architecture. The entrapped air pockets formed beneath the liquid droplet due to the formation of micro and nanometer-scale topographic features mainly attribute to the transition from hydrophilic Cu substrate to superhydrophobic Cu–ZrO2 hierarchical coating structure. In addition, high surface roughness along with the high value of the ratio between mean profile spacing (Sm) to mean profile width (Wa) facilitates the air entrapment in between the protrusions of the coated structure. Moreover, formation of low surface energy (111) crystal plane with respect to the CTAB loadings can be considered as another reason for the excellent hydrophobic behavior of the obtained Cu–ZrO2 coatings.

Improving dispersion stability of hydrochloric acid hydrolyzed cellulose nano-crystals

Cellulose nano-crystals (CNC) have attracted great interests as a novel nanostructured material in recent years, thanks to their excellent mechanical properties, high surface area and lightweight and biocompatibility etc. Due to its low charged group content, CNC prepared from the hydrochloric acid hydrolysis has poor dispersibility in water, which hinders its further applications. In this work, well-dispersed cellulose nano-crystals are successfully prepared using a two-step method, consisting of hydrochloric acid hydrolysis, followed by adsorption of hexadecyl trimethyl ammonium bromide (CTAB) onto CNC. Results show that CTAB at a low concentration (0.13–0.47 mM) provides effective steric barriers to minimize the CNC aggregation, which is supported by TEM images and particle size distribution of CNC. At high CTAB concentrations (>0.5 mM), CNC aggregation occurs, which is due to the “bridging” effect of CTAB.

Micellar Effect on Photoinduced Electron Transfer Reactions of Ruthenium(II) Polypyridyl Complexes with Quinones: Effect of CTAB

Photoinduced electron transfer reaction between the excited state ruthenium (II) polypyridyl complexes and quinones has been investigated in cetyltrimethylammonium bromide using luminescent quenching techniques. The complexes have the absorption and emission maximum in the range 452 - 468 nm and 594 - 617 nm respectively. The static nature of quenching is confirmed from the ground state absorption studies. The association constants for the complexes with quinones are calculated from the Benesi-Hildebrand plots using absorption spectral data. The value of quenching rate constant (kq) is highly sensitive to the nature of the ligand and the quencher, the medium, structure and size of the quenchers. Compared to the aqueous medium, the electron transfer rate is altered in CTAB medium. The oxidative nature of the quenching is confirmed by the formation of Ru3+ ion and quinone anion radical.

Optical properties and the band-gap variation in diverse Zn1-xSnxO nanostructures

In this work, Zn1-xSnxO nanostructures with diverse morphological characters were prepared by hydrothermal technique. The morphology, structure, crystallization and the chemical states of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization of UV–Vis spectra indicates that the optical transmittance of Zn1-xSnxO nanostructure is above 90% in the visible range. The optical absorption edge of the samples was determined according to the Tauc relationship, and a remarkable bule shift of the band-gap appeared for the Zn1-xSnxO nanomaterials. The fluorescence spectra were measured by using photoluminescence (PL) spectrometer. The pure ZnO nanostructure exhibits a strong yellow emission and a weak near-ultraviolet emission. The effect of CTAB is mainly on the photoluminescence intensity rather than the peak position. However, the introduction of stannum has an interesting effect on the PL of ZnO. The Zn1-xSnxO nanostructure exhibits a remarkable near-band-edge (NBE) emission with two peaks. The dependence of NBE emission spectra on excitation power was analyzed. Two radiative recombination channels of the NBE emission have been discussed in detail.

The effect of CTAB on Na2SO4 nucleation in mixed Na2SO4/CTAB aerosols by FTIR-ATR technology

Abstract FTIR-ATR technology is used to study the efflorescence kinetic of Na2SO4 and mixed Na2SO4/CTAB aerosols. As the RH decreased linearly, the ν3 SO42− band shifts from 1094 cm−1 to 1132 cm−1, suggesting the phase transition of Na2SO4 from solution to crystal phase (III). For pure Na2SO4 aerosols, the ERH is 75.1% RH, whereas the efflorescence point of mixed Na2SO4/CTAB aerosols (74.2%) is lower. By further analysis of IR differential spectra, the ratio of Na2SO4 crystals in mixed aerosols is only 62.7% and the heterogeneous nucleation rate of Na2SO4 in Na2SO4/CTAB mixed aerosols is lower than that in pure Na2SO4 aerosols. They showed that CTAB assembled into reversed micelle and part Na2SO4 droplets are in the core to form core-shell structure, and CTAB shell prevents core Na2SO4 solutions from crystallizing. However, the counter ion Br− for CTAB reversed micelle can interact with Na+ ions, which decreases the crystallization rate of free Na2SO4 droplets and ERH is delayed.

Improve the surface enhanced Raman scattering of gold nanorods decorated graphene oxide: The effect of CTAB on the electronic transition

The surface-enhanced Raman scattering (SERS) activity of the graphene oxide (GO) and Au nanorod (AuNR) hybrid (GO–AuNR) has been investigated by using the rhodamine 6G (R6G) as Raman active probe. Because of the existence of CTAB in the GO–AuNR substrate, the electronic transition efficiency has been greatly increased, which results in the significant improvement of SERS activity. A non-monotonous intensity change of SERS as a function of longitudinal surface plasmon resonance (SPR) wavelength has also been observed, which has been attributed to the aspect ratio-dependent competition between SPR and lightning rod effect.

Microwave synthesis and effect of CTAB on ferromagnetic properties of NiO, Co3O4 and NiCo2O4 nanostructures

Cubic-structured NiO, Co3O4 and spinel-structured NiCo2O4 were synthesized via microwave route. The structural properties of NiO, Co3O4 and NiCo2O4 nanostructures were investigated by X-ray diffraction analysis, and it showed smaller crystallite size for NiO than Co3O4 and NiCo2O4 by using Williamson–Hall method. Flake-like and hexagonal plate-like morphologies were ascertained from HRSEM and TEM analyses. Optical properties of these materials were investigated by photoluminescence study, and it presents the band edge emission for all materials with supplementary emissions in visible region due to the presence of defects such as vacancy and interstitial. Raman and FTIR spectra provide the functional characteristics of NiO, Co3O4 and NiCo2O4 nanostructures. XPS measurement revealed the purity and composition of these nanostructures. Room temperature magnetic measurements were investigated using vibrating sample magnetometer. The low coercivity and remanent magnetization for NiO, Co3O4 and NiCo2O4 nanostructures confirmed that these nanoparticles exhibit a weak ferromagnetic behaviour.

Synthesis of structural and optical characterization of surfactant capped ZnO nanocrystalline

The presence of surfactant (CTAB) at three different concentrations viz., (0.5, 1 and 1.5M) on zinc oxide (ZnO) nanocrystalline at 550°C was synthesized. The optical properties of each surfactant capped zinc oxide nanocrystalline were investigated using UV–Visible absorption. The characterization of these nanocrystalline was performed by X-ray diffractometer Spectrum (XRD), Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and Atomic force microscopy (AFM) and Fourier transformer infrared (FTIR) spectroscopy. The effect of CTAB on the morphology of the ZnO was studied by SEM/EDS which revealed that the diameter of the product is in the range of 42–70nm. Out of the three surfactant concentrations CTAB (0.5M) capped zinc oxide nanoparticle has smallest crystalline size of 19.4nm. Thus, the presence of surfactant on the surface of zinc oxide plays a significant role in reducing defect. The excitonic UV emission has been observed at 275nm.

Effect of CTAB as a foaming agent on the properties of alumina ceramic membranes

Alumina-ceramic membranes were prepared by gelcasting process using CTAB as a foaming agent. To increase the fineness, the starting alumina powder was milled for 1h in a ball mill before the casting process. Particle size distribution and surface area measurements of the as-received and milled alumina powder were examined. The casted alumina membranes were sintered at 1500°C. Sintering parameters in terms of bulk density (BD) and apparent porosity (AP) were determined by the Archimedes method. Pore size distribution of the sintered porous alumina membranes was measured using mercury porosimeter. Microstructure of sintered membranes was investigated by scanning electron microscope (SEM). Cold crushing strength (CCS) of the sintered specimens was also evaluated. The result revealed that the properties of porous ceramics such as porosity, average pore size, pore size distribution and cold crushing strength could be controlled by adjusting the preparation conditions e.g. solid loading, sintering temperature and foaming agent. The open porosity, cold crushing strength and average pore size of the alumina ceramics sintered at 1500°C were around 58.35%, 18MPa and178nm, respectively.

Synthesis of Poly(vinyl alcohol)-Silver Nanocomposites and Effect of CTAB on their Morphology

Synthesis of Poly(vinyl alcohol)-Silver Nanocomposites and Effect of CTAB on their Morphology Nacre-like film of silver-polyvinyl alcohol (PVA-water soluble biologically friendly polymer) nanocomposites is prepared via chemical reduction method, using tyrosine as a catalytic and reducing agent. Preparing of silver-PVA ordered layered nanocomposites by this method is done for the first time. The Ag- nanoparticles were characterized using UV-Vis spectroscopy, which shows an absorption band at 400-475 nm confirming the formation of nanoparticles. The results accord the formation of silver nanoclusters in conjunction with nanoparticles. The Ag nanoparticles were adsorbed in the PVA matrix through electrostatic interactions. PVA capped silver nanoparticles with or without cetyltrimethylammonium bromide, CTAB lead to the formation of nanostructures of various geometric shapes and sizes. Viscosity of the CTAB-PVA mixture was also determined. The role of PVA composition on the optical properties of silver nanoparticles has been examined and discussed.

The significance of the solid-to-liquid ratio in the electrokinetic studies of the effect of ionic surfactants on mineral oxides

The effect of SDS on the electrokinetic behavior of TiO2 and Al2O3 was studied by electrophoresis at various solid-to-liquid ratios. Additionally, the effect of CTAB on electrokinetic curves of Al2O3 single crystal and of Al2O3 particles was studied by streaming potential. At a sufficiently low solid-to-liquid ratio, the electrokinetic potential was negative and almost pH-independent in the presence of SDS and positive and pH-independent in the presence of CTAB. Further decrease in the solid-to-liquid ratio had a limited effect on the course of the electrokinetic curves. At a sufficiently high solid-to-liquid ratio, the electrokinetic potential was not affected by the presence of the surfactant. At moderate solid-to-liquid ratios, the electrokinetic potential in the presence of SDS was negative and almost pH-independent at very high and at very low pH, and less negative or even positive electrokinetic potential (more positive at higher solid-to-liquid ratios) was observed at moderate pH with a peak 1 to 2 pH units below the pristine IEP. The inspection of the results (obtained at single solid-to-liquid ratio) from the literature confirmed the above trends, also for oxides other than TiO2 or Al2O3. The range of solid-to-liquid ratios, which can be covered by electrophoresis is limited by insufficient signal, and by insufficient transparency at low and at high solid-to-liquid ratios, respectively. The available range of solid-to-liquid ratios can be extended by using the electroacoustic method.Apparently, the significance of the solid-to-liquid ratio in the electrokinetic studies of oxide-ionic surfactant systems is underrated. To our best knowledge, this is the first systematic study of such an effect ever published, and in many publications, the solid-to-liquid ratio was not reported and probably not even controlled.

The Effect of CTAB on the Citrate Sol-gel Process for the Synthesis of Sodium Beta-Alumina Nano-Powders

Sodium beta-alumina (SBA) nano-powders were synthesized by the citrate sol-gel process, and the effects of the cationic surfactant n-cetyltrimethylammonium bromide surfactant (CTAB) were investigated. The structure and morphology of the nano-powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques, respectively. The effects of CTAB on the citrate sol-gel process and the SBA formation were investigated by thermo gravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared spectroscopy (FTIR). The conductivity of ceramic pellets of SBA was measured by electrochemical impedance spectroscopy (EIS). The results showed that the CTAB inhibited the agglomeration of SBA powders effectively and consequently decreased the crystallization temperature of SBA, about <TEX>$150^{\circ}C$</TEX> lower than that of the sample without CTAB. The measured conductivity of SBA was <TEX>$1.21{\times}10^{-2}S{\cdot}cm^{-1}$</TEX> at <TEX>$300^{\circ}C$</TEX>.

Fluorescence quenching of naphthols by Cu2+ in micelles

Effect of the micelles of anionic, cationic and non-ionic surfactants on the fluorescence quenching of 1- and 2-naphthols has been studied in the presence of copper ion. The excited state lifetime, dynamic and static quenching constants for these systems have been determined. Fluorescence quenching in water and SDS micelle is due to the collision of the fluorophore with the quencher with a small static component. The negatively charged naphtholate ions in the excited state are quenched with significantly higher rates than the neutral naphthol molecules, which are located further inside the mesophase. CTAB micelle is less effective than the SDS micelle for fluorescence quenching. The effect of CTAB on water-assisted excited-state deprotonation has been investigated in the presence of ZnSO4. For TX-100 micelle there is negligible quenching even at higher concentration of the quencher.

Role of Organic and Inorganic Additives on the Assembly of CTAB-P123 and the Morphology of Mesoporous Silica Particles

Mesoporous silica particles with various morphologies and structures have been synthesized by controlling the solubility, micellization, and assembly of a charged surfactant (cethyltrimethylammonium bromide, CTAB) and a pluronic (PEO20PPO70PEO20, P123) couple using an organic (benzene) or an inorganic (SO42−, NO3−, or Cl−) additive. The effect of CTAB, with or without one of the Hofmeister ions or benzene in various concentrations, on the morphology, pore-size, pore-structure and the nature of the silica particles has been investigated. Increasing the lyotropic anion (SO42−) or benzene concentration of the synthesis media creates wormlike particles with enlarged pores and reduced wall thickness. However, the hydrotropic anion (NO3−) influenced the solubility of the charged surfactant and increased the CTAB concentration in the CTAB-P123 micelles, and as a result, in the mesoporous silica particles. The surface area, unit cell, and pore size of the silica particles are diminished by increasing the nitrate ...

Characterization of mesoporous alumina particles prepared by spray pyrolysis of Al(NO3)2·9H2O precursor: Effect of CTAB and urea

Mesoporous alumina particles with spherical shape were prepared by spray pyrolysis of Al(NO3)2·9H2O precursor. The surface area and the mesopores structure were investigated with varying the concentration of surfactant (cetyltrimethylammonium bromide, CTAB) and urea. The surface area and pore volume of alumina particles prepared by spray pyrolysis was greatly influenced by the CTAB/Al ratio, whereas, no significant change in the average pore size (3±0.2nm) was observed. According to the small-angle X-ray spectrum (SAXS) analysis, the prepared alumina had warm-like mesostructure. The d-spacing was slightly changed with varying the CTAB/Al ratio and correlated to the BET surface area and the number of CTAB micelles involved in making mesopores. It was found that the use of urea additive in the spray solution is helpful to increase the surface of alumina particles as well as the SAXS peak intensity due to the formation of mesostructures. In terms of the surface area and the pore regularity, the optimal CTAB/Al ratio and urea concentration was 0.1 and 3.0M, respectively.