Surfactant Brij Research Articles

Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis.

In this work, single-piece fused silica capillaries with two different internal diameter segments featuring different inner surface roughness were prepared by new etching technology with supercritical water and used for volume coupling electrophoresis. The concept of separation and online pre-concentration of analytes in high conductivity matrix is based on the online large-volume sample pre-concentration by the combination of transient isotachophoretic stacking and sweeping of charged proteins in micellar electrokinetic chromatography using non-ionogenic surfactant. The modified surface roughness step helped to the significant narrowing of the zones of examined analytes. The sweeping and separating steps were accomplished simultaneously by the use of phosphate buffer (pH 7) containing ethanol, non-ionogenic surfactant Brij 35, and polyethylene glycol (PEG 10000) after sample injection. Sample solution of a large volume (maximum 3.7 μL) dissolved in physiological saline solution was injected into the wider end of capillary with inlet inner diameter from 150, 185 or 218 μm. The calibration plots were linear (R2 ∼ 0.9993) over a 0.060-1 μg/mL range for the proteins used, albumin and cytochrome c. The peak area RSDs from at least 20 independent measuremens were below 3.2%. This online pre-concentration technique produced a more than 196-fold increase in sensitivity, and it can be applied for detection of, e.g. the presence of albumin in urine (0.060 μg/mL).

Synthesis of gold nanoparticles and thin films with the use of micellar solution of Brij 30

Gold nanoparticles (NPs) with the average core diameter d Au = 6.8 ± 1.6 nm have been synthesized in reverse micelles of the oxyethylated surfactant Brij 30. It has been shown that thin NP films can be produced directly from a micellar solution with the use of glass substrates functionalized with aminosilane. Synthesis of NPs and film formation have been studied by UV-Vis spectroscopy, photon correlation spectroscopy, X-ray diffraction, TEM, SEM, and AFM.

Rapid microwave-assisted synthesis of sub-30 nm lipid nanoparticles

HypothesisAccessing the phase inversion temperature by microwave heating may enable the rapid synthesis of small lipid nanoparticles. ExperimentsNanoparticle formulations consisted of surfactants Brij 78 and Vitamin E TPGS, and trilaurin, trimyristin, or miglyol 812 as nanoparticle lipid cores. Each formulation was placed in water and heated by microwave irradiation at temperatures ranging from 65°C to 245°C. We observed a phase inversion temperature (PIT) for these formulations based on a dramatic decrease in particle Z-average diameters. Subsequently, nanoparticles were manufactured above and below the PIT and studied for (a) stability toward dilution, (b) stability over time, (c) fabrication as a function of reaction time, and (d) transmittance of lipid nanoparticle dispersions. FindingsLipid-based nanoparticles with distinct sizes down to 20–30nm and low polydispersity could be attained by a simple, one-pot microwave synthesis. This was carried out by accessing the phase inversion temperature using microwave heating. Nanoparticles could be synthesized in just one minute and select compositions demonstrated high stability. The notable stability of these particles may be explained by the combination of van der Waals interactions and steric repulsion. 20–30nm nanoparticles were found to be optically transparent.

Nanostructure Changes upon Polymerization of Aqueous and Organic Phases in Organized Mixtures.

The nanostructure of a microemulsion can be strongly affected by the liquid-to-solid transition during polymerization. Here, we examined the evolution of nanostructures of different ternary mixtures, including two microemulsions and a single lamellar phase that upon polymerization are quantitatively studied by SAXS/WAXS and DSC experiments systematically performed before and after the polymerization of both aqueous and organic phases. Samples are mixtures of the poly(2-acrylamido-2-methylpropanesulfonic acid) network as the aqueous phase and poly(hexyl methacrylate) as the organic phase stabilized by Brij35 surfactant. Upon polymerization, the surfactant is excluded from the water/oil interface and crystallizes, strongly changing the nanostructure of samples where it is the main component. In samples where the aqueous phase is the main component, only a few changes in structure are observed upon polymerization. This study demonstrates quantitatively the possibility to preserve nanostructures during polymerization, thus inducing a templating effect.

Kinetic and mechanistic study of micellar effect of hydrolytic reaction of Di-2-methoxy-4-nitroaniline phosphate

ABSTRACTThe effect of anionic surfactant (sodium dodecyl sulphate) and nonionic surfactant (Brij-35) on the hydrolysis of di-2-methoxy-4-nitroaniline phosphate was studied spectrophotometrically at 303 K. The influence of salts on the reaction rate was studied. The presence of inorganic salts (KCl, KNO3, and K2SO4) exhibited positive effect on the reaction rate. The thermodynamic activation parameters were calculated from Arrhenius equation. On the basis of the experimental findings a suitable mechanism has been proposed. The binding constants between the reactants and the surfactants evaluated from the kinetic models proposed by Menger-Portnoy, Piszkiewicz, and Berezin have been found in good agreement.

Nonionic surfactant structure on the drug release, formulation and physical properties of ethylcellulose microspheres

Evaluate the effects of nonionic surfactants Brij 58 and Tween 40 with different structures but similar hydrophilic lipophilic balances (HLBs) on theophylline (TH)-loaded ethylcellulose (EC) microspheres. Microspheres were formulated using ratios of the surfactants with matching HLB values but different chemical-structures at temperatures (22/35 °C) by hydrophobic solvent-emulsion evaporation. Particle size, GMD, drug loading, encapsulation efficiency and dissolution were evaluated. Drug release was determined using the zero- and first-order, Higuchi and Hixson–Crowell models. EC microspheres prepared with surfactant Brij 58 showed discrete, free-flowing spherical particles, solid interiors and increased particle smoothness as temperature increased; those prepared with Tween 40 appeared porous with coarser surface morphology as temperature increased; both were CHLB (Combined HLB) dependent. Dissolution obeyed the Higuchi model drug release for both microspheres prepared with Tween 40 and Brij 58 except for those prepared with Brij 58 at 35 °C, which presented as zero order. The results were ascribed to the different chemical structure of Brij 58 versus Tween 40 and preparation temperature. Surfactant chemical structure is an unreported processing parameter shown here to be important in microsphere formulation. Brij 58 possesses properties unique to its chemical structure that influence pharmaceutical and molecular biopharmaceutical research.

Adsorption of nonionic Brij and Tween surfactants at PTFE-water and air-water interfaces: Investigations on wetting, dispersion stability, foaming and drug solubilization

Aqueous solutions of nonionic surfactants, namely Brij O10, Brij 35, Brij 98, Tween 20, Tween 60 and Tween 80 are investigated to understand their diffusion from the bulk solution to the surface and adsorption processes at PTFE-water interface using dynamic surface tension (DST), water penetration in packed PTFE powder and rate of sedimentation measurements. DST correlates well with the water penetration in packed PTFE powder (wettability) and the rate of sedimentation in aqueous dispersions for Brij surfactants. The results are described in terms of the structural features and HLB of respective surfactant and its ability to diffuse and adsorb at the interface. Brij O10 and Tween 60 showed maximum wettability and dispersion stability for respective series. We correlate the dynamic surface tension with interfacial phenomenon e.g. water penetration in the packed PTFE powder and the rate of sedimentation for aqueous dispersions. The diffusion towards air-water interface was essentially controlled by the molecular weight of the surfactant, while adsorption on the hydrophobic PTFE is controlled by the HLB of the respective surfactant molecule. We introduce a strategy to use PTFE particles as model for aqueous formulations involving hydrophobic drugs. The water penetration, wettability and stability of PTFE dispersions increase with lower DST values.

Surfactant and metal ion effects on the mechanical properties of alginate hydrogels

This paper addresses the controlled variation of the mechanical properties of alginate gel beads by changing the alginate concentration or by adding different surfactants or cross-linking cations. Alginate beads containing nonionic Brij 35 or anionic sodium dodecyl sulfate (SDS) surfactants were prepared with two different types of cations (Ca2+, Ba2+) as crosslinkers. Compression measurements were performed to investigate the effect of the surfactant and cation types and their concentrations on the Young’s modulus of alginate beads. The Young’s modulus was determined by using Hertz theory. For all types of alginate gel beads the Young’s modulus showed an increasing value for increasing alginate contents. Addition of the anionic surfactant SDS increases the Young’s modulus of the alginate beads while the addition of non-ionic surfactant Brij 35 leads to a decrease in Young’s modulus. This opposite behavior is related to the contrary effect of both surfactants on the charge of the alginate beads. When Ba2+ ions were used as crosslinker cation, the Young’s modulus of the beads with the surfactant SDS was found to be approximately two times higher than the modulus of beads with the surfactant Brij 35. An ion specific effect was found for the crosslinking ability of divalent cations.

LC of high to moderately polar basic drugs in urine with water and detergent, and direct injection.

Micellar LC was first proposed as a 'green' mode using mobile phases of water and surfactant. However, in most procedures a small amount of organic solvent is required to decrease the retention to convenient values. Results & methodology: Mixed micellar mobile phases prepared with both cationic (sodium dodecyl sulphate) and nonionic surfactant (Brij-35) modulate the retention of high to moderately polar basic drugs to practical times, eliminating the need of organic solvent. While the mobile phase is continuously recycled through the system, the stationary phase performance is maintained after repetitive injection of the samples. Through an extensive validation, the approach is shown to be appropriate to determine these drugs in urine samples without previous pretreatment.

Wheat straw biochar amendments on the removal of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil

Soil amendments of wheat straw biochar (BC), lignocellulosic substrate (LS), BC+LS, and BC+LS+BR (surfactant Brij30) were investigated for the first time in order to remedy polycyclic aromatic hydrocarbons (PAHs)-polluted soil using pilot scale microcosm incubation. We hypothesized that the removal of PAHs could be inhibited due to the adsorption and immobilization of biochar and the inhibition depends on the molecular-weight of PAHs. The removal rates of phenanthrene (PHE) and Benzo[a]pyrene (BaP) ranked as C=BC>LS=LS+BC=LS+BC+BR and C=BC=LS+BC+BR>LS=LS+BC. Wheat straw biochar inhibited the removal of PHE and accelerated BaP removal. The activity of Dehydrogenase (DH) was depressed by the addition of the biochar while the activity of polyphenol oxidase (PPO) was stimulated. Lignocellulose and surfactant are favourable to sustain soil microbiological activity and the removal of PAHs although the diversity of bacterial community was not significantly changed. The findings implied that the components of PAHs are necessary to consider when the amendments are implemented by associated biochar in PAH-polluted soil.

Polyacrylic acid and polyacrylamide as cloud point modifier for Brij-30 in alcoholic aqueous solution

ABSTRACTCloud point (CP) measurement of aqueous nonionic surfactant Brij-30 was studied at various concentrations of surfactants in pure and mixed system with water-soluble polymers polyacrylicacid (PAA) and polyacrylamide (PAM). The CP of Brij-30 was found to increase on increasing the surfactant concentration. The CP of Brij-30 was to initially decrease with the addition of PAA and then increase with further addition of PAA. The CP of Brij-30 was to increase with increase in concentration of PAM. The same trend was observed for all surfactant concentrations in the presence of PAA and PAM, respectively. Considering CP as a threshold temperature of the solubility, the thermodynamic parameters of the clouding process (Δ, Δ, and Δ) were evaluated using the “Phase Separation Model”. The results indicate that the clouding phenomenon of Brij-30 is exothermic and in the presence of additives it is an endothermic and nonspontaneous process.

Simultaneous detection of trace metal ions in water by solid phase extraction spectroscopy combined with multivariate calibration

Solid Phase Extraction Spectroscopy (SPES) developed in this paper is a technique to measure spectrum directly on the solid phase material where the analytes are concentrated in SPE process. Membrane enrichment and UV–Visible spectroscopy were utilized to fulfill SPES, and multivariate calibration method of partial least squares (PLS) was used to simultaneously detect the concentrations of trace cobalt (II) and zinc (II) in water samples. The proposed method is simple, sensitive and selective. The complexes of analyte ions were collected on the cellulose acetate membranes via membrane filtration after the complexation reaction with 1-2-pyridylazo 2-naphthol (PAN). The spectra of the membranes which contained the complexes of metal ions and PAN were measured directly without eluting. The analytical conditions including pH, reaction time, sample volume, the amount of PAN, and flow rates were optimized. Nonionic surfactant Brij-30 was absorbed on the membranes prior to SPES to modify the membranes for improving the enrichment and spectrum measurement. The interference from other ions to the determination was investigated. Under the optimal condition, the absorbance was linearly related to the concentration at the range of 0.1–3.0μg/L and 0.1–2.0μg/L, with the correlation coefficients (R2) of 0.9977 and 0.9951 for Co (II) and Zn (II), respectively. The limits of detection were 0.066μg/L for cobalt (II) and 0.104μg/L for zinc (II). PLS regression with leave-one-out cross-validation was utilized to build models to detect cobalt (II) and zinc (II) in drinking water samples simultaneously. The correlation coefficient between ion concentration and spectrum of calibration set and independent prediction set were 1.0000 and 0.9974 for cobalt (II) and 1.0000 and 0.9956 for zinc (II). For cobalt (II) and zinc (II), the errors of the prediction set were in the range 0.0406–0.1353μg/L and 0.0025–0.1884μg/L.

Facile Fabrication of Platinum Nanodots Assembly Core–Silica Shell Nanosystems

Nanosystems using a platinum (Pt) nanodots assembly (multi-Pt nanoparticles, m-Pt) as the core and silica (SiO2) shells were successfully synthesized as m-Pt@SiO2 spherical nanoparticles (NPs) and m-Pt@SiO2 nanochains (NChs) by a reverse microemulsion (water-in-oil)-based method. The kinetically controlled reduction of K2PtCl4 by the Brij35 surfactant within reverse micelles, followed by condensation of tetraethyl orthosilicate, led to the formation of multi-Pt nanodots core–silica shell systems. The reduction kinetics for the growth of core–shell systems was studied in both the presence of reducing agents such as ascorbic acid, glucose, and ethylene glycol and in the absence of supplementary agents, as well as the variation of water-to-surfactant ratio. To assemble Pt NPs within a one-dimensional SiO2 matrix, we attempted to grow Pt NPs in␣situ while the SiO2 materials grew one-dimensionally in a modified microemulsion system. By changing the pH of the reaction media or using highly concentrated ethylene glycol in the synthetic approach, we successfully synthesized m-Pt@SiO2 NChs.

The effect of concentration of surfactant and electrolyte on the pit and droplet sizes nanoemulsions of n-dodecane in water

Nanoemulsions are transparent or semi-transparent systems mostly covering the size range of 50–200 nm. In the research, the production of nanoemulsion of n-dodecane in water was studied by phase inversion temperature method (PIT), and the effect of the changes in NaCl and surfactant concentration on PIT and droplet size of n-dodecane was studied. The changes in conductivity with temperature were measured for emulsions containing 20 wt % dodecane, 4 and 8 wt % Brij30, and NaCl of various concentrations in aqueous phase. The results showed a decrease in PIT with a rise in concentration of NaCl and also Brij30. There was a linear model fitted to the data. Analysis of variance (ANOVA) shows that, the significance value (p-value) is less than 0.05, and the effect of the changes in concentration of surfactant Brij30 on the decrease in PIT and droplet size was the more than that in concentration of NaCl in aqueous phase. The lowest mean droplet diameters were in the range of 8.6–14 nm.

Effects of Two Surfactants and Beta-Cyclodextrin on Beta-Cypermethrin Degradation by Bacillus licheniformis B-1.

The biodegradation efficiency of beta-cypermethrin (β-CY) is low especially at high concentrations mainly due to poor contact between this hydrophobic pesticide and microbial cells. In this study, the effects of two biodegradable surfactants (Tween-80 and Brij-35) and β-cyclodextrin (β-CD) on the growth and cell surface hydrophobicity (CSH) of Bacillus licheniformis B-1 were studied. Furthermore, their effects on the solubility, biosorption, and degradation of β-CY were investigated. The results showed that Tween-80 could slightly promote the growth of the strain while Brij-35 and β-CD exhibited little effect on its growth. The CSH of strain B-1 and the solubility of β-CY were obviously changed by using Tween-80 and Brij-35. The surfactants and β-CD could enhance β-CY biosorption and degradation by the strain, and the highest degradation was obtained in the presence of Brij-35. When the surfactant or β-CD concentration was 2.4 g/L, the degradation rate of β-CY in Brij-35, Tween-80, and β-CD treatments was 89.4%, 50.5%, and 48.1%, respectively. The half-life of β-CY by using Brij-35 was shortened by 69.1 h. Beta-CY content in the soil with both strain B-1 and Brij-35 decreased from 22.29 mg/kg to 4.41 mg/kg after incubation for 22 d. This work can provide a promising approach for the efficient degradation of pyrethroid pesticides by microorganisms.

Folding of newly translated membrane protein CCR5 is assisted by the chaperonin GroEL-GroES.

The in vitro folding of newly translated human CC chemokine receptor type 5 (CCR5), which belongs to the physiologically important family of G protein-coupled receptors (GPCRs), has been studied in a cell-free system supplemented with the surfactant Brij-35. The freshly synthesized CCR5 can spontaneously fold into its biologically active state but only slowly and inefficiently. However, on addition of the GroEL-GroES molecular chaperone system, the folding of the nascent CCR5 was significantly enhanced, as was the structural stability and functional expression of the soluble form of CCR5. The chaperonin GroEL was partially effective on its own, but for maximum efficiency both the GroEL and its GroES lid were necessary. These results are direct evidence for chaperone-assisted membrane protein folding and therefore demonstrate that GroEL-GroES may be implicated in the folding of membrane proteins.

Surfactant-doped reverse-mode polymer-dispersed liquid crystal display with enhanced properties

ABSTRACTIn this article, a nonionic surfactant Brij30 has been used to vertical align the negative anisotropic liquid crystal. The surfactant is further used in reverse-mode polymer-dispersed liquid crystal display to enhance the electro-optical properties. This work shows an enhancement of contrast ratio simply with the addition of surfactant. In addition, contact angle and surface free energies have been determined to judge the role of surfactant in control of surface orientation of liquid crystal molecules.

Effect of mixed micellization on dimensions of 1-butyl-3-methylimidazolium dodecylsulfate micelles in presence of electrolytes

Abstract The association behavior of an amphiphilic ionic liquid 1-butyl-3-methylimidazolium dodecylsulfate ([bmim][DS]) and a non-ionic surfactant Brij30, in the presence and absence of NH4Cl and NaCl, was investigated using DLS, SANS and Rheology. The apparent hydrodynamic radius (Rh) of the mixed micelles increases with increase in mole fraction of the non-ionic component. The variation in micellar size with Brij30 mole fraction is sensitive to the nature and concentration of the two salts. The increase in size of mixed micelles is more pronounced in presence of NH4Cl than NaCl, owing to higher salting out effect of NH4+ ions compared to Na+ ions. The hydrodynamic radius of the mixed mcielles decreases with increase in temperature from 25 °C to 45 °C, due to dehydration of oxyethylene units in Brij30. SANS studies reveal that [bmim][DS] micelles grow significantly with increase in Brij30 mole fraction and the presence of salt facilitates micellar elongation. The zero shear viscosity of mixed micelles in the presence of 0.4 M NH4Cl and NaCl increases with Brij30 mole fraction, the effect being more in presence of the former.

Effect of Natural and Synthetic Surfactant on the Rheology of Light Crude Oil

Comparative effectiveness of natural surfactant extracted from Sapindus mukorossi in laboratory and commercial surfactant Brij 30 was determined. Light crude oil was collected from ONGC, Gujarat, India. Its pour point and viscosity decreased significantly after adding surfactants. Wax crystal structure and crystal size distribution was analyzed using cross polarized light microscope and dynamic light scattering techniques. There was remarkable reduction in radius of wax crystals after addition of both the surfactants. Microscopic studies showed significant change in size and structure of wax crystals favoring reduction in viscosity. The possible mechanism behind improvement of flow properties was also analyzed through FTIR studies.

Synthesis of Iron Oxide Nanoparticles by Different Methods and Study of their Properties

In this work, iron oxide nanoparticles have been synthesized by precipitation in diethylene glycol, by cryochemical synthesis, in microemulsions using surfactants Triton X-100, Brij-35 and CTAB. Comparative spectroscopic, thermal, X-ray diffraction, 57Fe zero-field Mössbauer and magnetic studies of the synthesized nanoparticles have been carried out. Magnetic fluids prepared from synthesized nanopowders have been characterized by calorimetric measurements of specific loss power (SLP).