Concentrations Of Tetradecyl Trimethyl Ammonium Bromide Research Articles

Interactions of nanocrystalline cellulose with an oppositely charged surfactant in aqueous medium

The interaction between negatively charged nanocrystalline cellulose (NCC) and a cationic surfactant, tetradecyl trimethyl ammonium bromide (TTAB) was examined by isothermal titration calorimetry (ITC), conductometric and potentiometric titrations and surface tensiometry. The interaction is controlled by electrostatic and hydrophobic interactions. ITC and surface tension measurements confirmed the formation of electrostatically driven NCC–TTAB complexes in the bulk and at the interface, which was followed by hydrophobically driven polymer-induced micellization of TTAB on NCC rods. The critical micelle concentration (CMC) of TTAB was shifted from 1.1 to 1.3g/L in the presence of 0.655g/L NCC. The settling and phase separation characteristics were quantified by determining the height of NCC flocs as a function of time, which describe the stability of NCC in the presence of TTAB. Zeta potential results revealed a charge reversal from negative to positive values with increasing TTAB concentration, confirming the formation of NCC–TTAB complexes in aqueous solutions. Based on the results, a physical mechanism on the interaction of NCC and TTAB is proposed.

Thermotropic Liquid Crystalline Phases in Binary Mixture of Nonmesogenic Compounds

The binary mixture of two nonmesogenic compounds viz., Tetradecyl Trimethyl Ammonium Bromide (TTAB) and Orthophosphoric acid (H3PO4) exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperature. The mixture with lower and higher concentrations of TTAB exhibits Sm A, Sm D, Sm B, and Sm E phases, sequentially when the specimen is cooled from its isotropic phase. Different liquid crystalline phases observed in the mixture were studied using DSC, X-ray, and Optical microscopic techniques. The temperature variation of optical anisotropy has also been discussed. Helfrich potential and elastic moduli have been estimated in the smectic phase using Helfrich model.

Micellar Nematic Phase in a Binary Mixture of Two Nonmesogenic Compounds

We report the results of our studies on the optical and thermal properties of two nonmesogenic compounds, namely, tetradecyl trimethyl ammonium bromide (TTAB) and glacial acetic acid (GAA). The mixture exhibits very interesting schilieren texture of micellar nematic lyophase, smectic A (SmA), and SmG phases for all concentrations of TTAB sequentially when the specimen is cooled from its isotropic phase. The order parameter (S) of the micellar nematic phase is estimated with the help of temperature dependence of optical anisotropy from the measured refractive index and density data. The temperature variation of order parameter of the experimental curve is very well fitted with the Mayer–Saupe theoretical curve. The temperature variation of electrical conductivity is also discussed. The formation of above phases has been confirmed by optical X-ray and differential scanning calorimetry studies.

Micellar Enhanced Base Catalyzed Hydrolysis of Ethyl Acetate Using TTAB

Surfactants can increase the low rate of heterogeneous liquid-liquid reactions involving partially miscible substrates through formation of micelles. This is a direct consequence of higher solubilization of substrates by micelles in reaction zones. In this case, rate enhancement of NaOH (base) catalyzed hydrolysis of ethyl acetate was studied. Micelles by cationic surfactant tetradecyl trimethyl ammonium bromide (TTAB) made the rate enhancement. In the presence of NaOH, CMC (critical micellar concentration) of TTAB decreases from its original value and attains the value of 2.97 × 10-4 M. In the absence of TTAB, the second order rate constant increases linearly with temperature. The hydrolysis reaction follows second order kinetics at different temperatures in the presence of different concentrations of TTAB. For a particular temperature, on addition of TTAB beyond CMC, rate constant first increases sharply and then becomes almost constant. At TTAB concentration of 1.485 × 10-3 M, rate constant attains maximum value (2.65 times of rate constant without TTAB) and then it becomes almost constant. The applied model successfully explains change in rate constant due to incorporation of micelles by the addition of TTAB. This model involves certain assumptions like one substrate molecule is solubilized in one micelle; substrate molecule doesn't form a complex with monomer of surfactant; and no competitive inhibition occurs during reaction. Correlations between bulk phase rate constant (k0), micellar phase rate constant (km) and temperature (T) are incorporated into the model for this particular system.

The chain length influence of cationic surfactant and role of nonionic co-surfactants on controlling the corrosion rate of steel in acidic media

The corrosion inhibition effect of cationic surfactants, DTAB (Dodecyl Trimethyl Ammonium Bromide) and TTAB (Tetradecyl Trimethyl Ammonium Bromide), on low carbon steel was studied using weight loss, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements. The effect of chain length compatibility on corrosion inhabitancy of surfactant and co-surfactant was investigated by C 7OH (1-heptanol), C 12OH (1-dodecanol) and C 15OH (1-pentadecanol) as nonionic co-surfactants in acidic media at different concentrations of DTAB and TTAB. Data represented that the corrosion rate decreased by increasing concentration of DTAB and TTAB, independently. The effect of chain length compatibility on surfactant behavior was discussed. Decreasing of corrosion rate for DTAB + C 12OH was more pronounced than other mixtures.

AN INSIGHT INTO COLLOIDAL GAS APHRON DRAINAGE USING ELECTRICAL CONDUCTIVITY MEASUREMENT

In the present paper Electrical Conductivity (EC) of Colloidal Gas Aphron (CGA) suspensions was measured for anionic and cationic surfactants (Sodium Dodecyl Sulfate (SDS) and Tetradecyl Trimethyl Ammonium Bromide (TTAB)). Experiments were made for different concentrations of SDS (6, 8.1, 10 mM) and TTAB (2, 3.51, 5 mM). CGA drainage behavior was observed and measured using 1 liter measuring cylinder while recording EC. Studying the results, CGA drainage process was observed as four-phase mechanism, instead of three conventional phases. Regardless of surfactant concentration and type, the drainage process is divided in to absorption, macroscopic, bubble, and microscopic phases. Drainage rate did not change at the end of bubble phase, with the maximum value at the end of absorption phase. Results showed that electrical conductivity is a more sensitive property for studying CGA characterization.

Chemical synthesis and crystallization of the dipeptide AcPheIleNH 2 in TTAB/heptane/octanol reversed micelles

The chemical synthesis of the dipeptide acetyl phenyl isoleucinamide (AcPheIleNH 2) in tetradecyl trimethyl ammonium bromide (TTAB)/ heptane/octanol/carbonate buffer reversed micelles is described. The co-existence of the surfactant bounded minute water pools within the bulk organic solvent enables the simultaneous solubilization of the polar (IleNH 2) and apolar (AcPheOEt) substrates, thus enabling the synthesis to take place at the micellar interface. The synthesis was favored by increasing the micellar interface via an increase in water content and surfactant concentration. The best dipeptide yield (87%) was obtained at 32 °C, with the largest concentrations of TTAB (200 mM) and water (1100 mM) tested. The low solubility of the dipeptide in the micellar media further led to the formation and growth of needle-like crystals during synthesis, thus enabling the removal of product from solution.

Amidase encapsulated in TTAB reversed micelles for the study of transamidation reactions

Amidase, an amide hydrolase enzyme (E.C.3.5.1.4) with acyl transferase activity, was encapsulated in a reversed micellar system composed of the cationic surfactant tetradecyltrimethyl ammonium bromide (TTAB) in heptane/octanol (80/20%) and phosphate buffer at w0 11. The reaction used to study the effect of the reversed micellar system on the enzyme behaviour was a transamidation reaction. The effect of surfactant concentration, buffer molarity and pH on the enzyme kinetics was evaluated. Both initial velocities and product yield were measured. The results indicated that a high initial velocity of hydroxamic acid synthesis and also the highest yield (98%) were obtained using the lowest pH value. The effect of TTAB concentration was dependent on the buffer molarity used. The effect of buffer molarity on reversed micelle dimensions was analysed by light scattering. These results showed that the buffer molarity had a strong influence on the reversed micelle radius that correlated with enzyme activity.

Some structural transformations in TTAB aggregated ternary systems as seen by positron lifetime spectroscopy

Positron lifetime spectroscopy (PLS) has been used to investigate structural transformations in TTAB aggregated ternary systems. Positron lifetime measurements were performed as a function of the concentration of pentanol in tetradecyl trimethyl ammonium bromide (TTAB)/water/pentanol systems having initial concentrations of TTAB in water as 20, 30 and 40 wt.%. For the systems studied, characteristic changes were observed in the positron lifetime parameters whenever a phase transformation occurs. The various phase boundaries demarcated by this technique agrees well with those obtained by other conventional techniques. Besides this, the present work suggests the existence of two kinds of lamellar structures referred to as D I and D II phases in the system, which were otherwise considered to be a single D phase by other conventional techniques. The existence of such lamellar structures has been demonstrated by a change in the trend of ortho-positronium ( o-Ps) lifetime when the system passes from one type of lamellar structure to the other type.

Cleavage of the SS bond in 5,5′-dithiobis-(2-nitrobenzoic acid) in the presence of a cationic detergent An approach to the cleavage of the SS bond in bovine plasma albumin

The hydrolysis of 5,5′-dithiobis-(2-nitrobenzoic acid) was studied at pH 9.20 and 25°C in presence of tetradecyltrimethylammonium bromide or micellar tetradecyltrimethylammonium bromide. The reaction was pseudo-unimolecular reaction with regard to the concentration of dithionitrobenzoic acid. The rate constant k 1 depended on the tetradecyltrimethylammonium bromide concentration and on the ionic strength of the buffer solution. At a constant ionic strength, the value of k 1 increased with the increase in the tetradecyltrimethylammonium bromide concentration, attained maximum at a certain concentration above the critical micelle concentration, and then decreased. The value of k 1 was larger when the ionic strength was lower. The rate of hydrolysis at the ionic strength 0.1 was the same as that without tetradecyltrimethylammonium bromide. On the contrary, sodium dodecyl sulfate or micellar sodium dodecyl sulfate had no effect on the rate of hydrolysis. These results lead to the conclusion that the SS bond is cleaved easier, when it is surrounded by the cationic detergent. The SH/S-S exchange reaction of bovine plasma albumin in the presence of cationic detergent was slower when the ionic strength was higher. The fact could be explained by assuming that the exposed SS bond is surrounded by the cationic detergent. Further, it was speculated that some SS bonds in albumin are surrounded by the positively charged basic amino acid residues.