Solvation Dynamics of Coumarin 480 in Bile Salt−Cetyltrimethylammonium Bromide (CTAB) and Bile Salt−Tween 80 Mixed Micelles

2003 ◽  
Vol 107 (49) ◽  
pp. 13643-13648 ◽  
Author(s):  
Debdeep Chakrabarty ◽  
Partha Hazra ◽  
Anjan Chakraborty ◽  
Nilmoni Sarkar
Keyword(s):  
Bile Salt ◽  
Cetyltrimethylammonium Bromide ◽  
Mixed Micelles ◽  
Tween 80 ◽  
Solvation Dynamics

scholarly journals Μελέτη της διεπιφανειακής συμπεριφοράς μικυλλίων στο σύστημα Hg-ηλεκτρολυτικό διάλυμα

2001 ◽  
Author(s):  
Σπυρίδων Αντωνίου
Keyword(s):  
Phase Transformations ◽  
Cetyltrimethylammonium Bromide ◽  
Mixed Micelles ◽  
Adsorbed Layer ◽  
Tween 80 ◽  
Differential Capacitance ◽  
Mean Field Approximation ◽  
Precipitation Process ◽  
Sodium Dodecylsulphate ◽  
Bulk Solutions

In the present study, the adsorption of micelles on an electrode surfaceis studing theoretically, by means of Statistical Thermodynamics, andexperimentally, by means of differential capacitance measurements.A simple model is developed to describe the single adsorption of amonomer neutral organic compound on an ideally polarized electrode surface.The equilibrium properties are determined within the framework of latticestatistics using the mean field approximation under the assumption of a meanelectrical field acting at each site. Neglecting short-range interactions, themodel for single adsorption predicts langmuirian adsorption isotherms, whichare congruent only with respect to potential, and a quadratic dependence of theGibbs energy of adsorption on the potential.The model is extended to include aggregation phenomena leading to theformation of surface micelles and phase transformations of the adsorbed layer.The model predicts that the formation of oligomers is not depicted in thecapacitance plots, which exhibit the same features as those for adsorption ofmonomers under all circumstances. The equilibrium between monomers andoligomers extends throughout the polarization range where these two states ofthe adsorbate coexist. As the number of monomer units in the micellesincreases, monomers and micelles tend to separate, occupying differentpolarization regions. In addition, the equilibrium between monomers and largeaggregates leads in general to complicated capacitance plots characterized bythe appearance of very sharp capacitance peaks. The same featurescharacterize the formation of mixed two-dimensional micellar films on electrodesurfaces. Phase transformations of adsorbed monolayers on electrodesurfaces, which may lead to the formation of either two immiscible concentratedsurface solutions of adsorbate in solvent and vice versa or pure adsorbateprecipitate, are examined within the framework of this model. The separation o the adsorbed layer to immiscible surface solutions is related to the short-rangeparticle-particle interactions, whereas the surface precipitation process isconsidered as an aggregation process where the aggregation number tends toinfinity. It is shown that in general there is an acceptable agreement betweentheory and experiment.The formation and properties of mixed micellar films on the Hg electrodein the presence of two surfactants in the electrolyte solution is studied bymeans of differential capacity measurements. The experimental study isperformed with a system consisting of a potensiostat, a lock-in amplifier and astandard electrochemical cell with a HDME electrode. The system wascontrolled through a PC with an appropriate software, which was developed forthis study.The experimental data are analyzed on the basis of the present andprevious theoretical treatments. It is found that the system sodiumdodecylsulphate - cetyltrimethylammonium bromide exhibits two differentbehaviours: At bulk solutions rich in sodium dodecylsulphate a film of mixedmicelles covers the electrode surface from positive polarizations up to - I.6V(see). In contrast, at bulk solutions rich in cetyltrimethylammonium bromide theelectrode surface is covered with a bilayer of micelles composed exclusively ofcetyltrimethylammonium cations, which negative of - 1.2 V (see) collapses to acondensed layer due to the penetration of dodecylsulphate anions. When theelectrolyte solution contains sodium dodecylsulphate and tween 80, then underfavourable conditions the electrode is covered with micelles of puredodecylsulphate anions from positive potentials up to the first capacitance peakat negative potentials. Negative of this peak and up to the second peak at farnegative potentials the electrode is covered with mixed micelles rich in tween80. Finally, in the system of tween 80 -cetyltrimethylammonium bromide theelectrode is covered with a film of mixed micelles, possibly of variablecomposition, throughout the range of potentials we studied.

Solvation Dynamics of Coumarin 480 in TritonX-100 (TX-100) and Bile Salt Mixed Micelles†

2003 ◽  
Vol 107 (31) ◽  
pp. 5887-5893 ◽  
Author(s):  
Debdeep Chakrabarty ◽  
Partha Hazra ◽  
Nilmoni Sarkar
Keyword(s):  
Bile Salt ◽  
Mixed Micelles ◽  
Solvation Dynamics

scholarly journals Prospects for the use of mixed micellar structures as a template in synthesis of MCM-41-type silicas

2021 ◽  
pp. 79-89
Author(s):  
N.V. Roik ◽  
◽  
L.O. Belyakova ◽  
М.О. Dziazko
Keyword(s):  
Azo Dye ◽  
Cetyltrimethylammonium Bromide ◽  
Mixed Micelles ◽  
Hydrophobic Interactions ◽  
Sol Gel ◽  
Standard Free Energy ◽  
Reaction Medium ◽  
Total Pore Volume ◽  
Methyl Red ◽  
Sol Gel Synthesis

Formation of mixed micelles assisted by cetyltrimethylammonium bromide and methyl red was studied by means of conductometric and spectrophotometric methods. It follows from the analysis of conductometric dependences that the addition of azo dye leads to a decrease in critical micelle concentration of a long-chain quaternary ammonium salt. The respective thermodynamic parameters were calculated. The process of mixed micelles formation was stated to be spontaneous and the solubilization of azo dye by micelles of cetyltrimethylammonium bromide is profitable in terms of energy and accompanied by an increase in degrees of freedom of the system. Based on the data of spectrophotometric study of methyl red solutions in the presence of cetyltrimethylammonium bromide, the values of stability constant, partition coefficient and change in the standard free energy of methyl red distribution between aqueous and micellar medium were calculated. It was found that electrostatic and hydrophobic interactions arising between azo dye and cetyltrimethylammonium bromide molecules cause the orientation of methyl red from the shell towards the center of the micelles. It was shown that mixed micelles can be used as a template in sol-gel synthesis of mesoporous aminosilica of MSM-41 type. The results of low-temperature nitrogen adsorption-desorption and X-ray analysis revealed that the introduction of methyl red as a part of mixed micelles into the reaction medium of sol-gel synthesis causes substantial increase in specific surface area and total pore volume, noticeable reduction of pore diameter, thereby contributing to the formation of silica material with a pronounced long-range ordered mesoporous structure.

Bile salt hydrophobicity and phosphatidylcholine acyl chain composition in vesicles and mixed micelles from model and human gallbladder bile

1995 ◽  
Vol 108 (4) ◽  
pp. A1154
Author(s):  
W. Renooij ◽  
K.J. van Erpecum ◽  
B.J.M. van de Heijning ◽  
P. Portincasa ◽  
G.P. vanBerge-Henegouwen
Keyword(s):  
Bile Salt ◽  
Mixed Micelles ◽  
Acyl Chain ◽  
Gallbladder Bile ◽  
Human Gallbladder ◽  
Chain Composition ◽  
Acyl Chain Composition

Pluronic®-bile salt mixed micelles

2018 ◽  
Vol 166 ◽  
pp. 119-126 ◽  
Author(s):  
Vijay Patel ◽  
Debes Ray ◽  
Anita Bahadur ◽  
Junhe Ma ◽  
V.K. Aswal ◽  
...  
Keyword(s):  
Bile Salt ◽  
Mixed Micelles
Sign in / Sign up

Export Citation Format

Share Document