Absorption spectra of 7, 7, 8, 8-tetracyanoquinodimethane in micellar solutions

Spectrophotometric and Thermodynamic Studies of Micellar Interaction of Surfactants withp-Nitrophenol

“…Jana et al [10] and Oldfield et al [16] feel that such behavior could be explained for NPH to be located at the interface (consisting of surfactant micelle, its counter ions, and the interfacial aqueous phase). Appearance of the absorption spectrum of NPH with a small red-shift and simultaneous increase in the band intensity were interpreted as due to the incorporation of NPH into water-rich Stern Layer of the micelles.…”

“…Formation of 1:1 chargetransfer (CT) or electron donor-acceptor (EDA) complexes has been proposed in the dye-surfactant interaction studies by many workers. [9,10,13,15,32] Increase in the intensity of the absorption band at ca. 402 nm at the expense of the 318 nm band intensity suggests that the ''new species'' formed, absorbs in the same region as that of the phenolate-anion.…”

“…[1][2][3][4][5][6][7] When one critically examines these systems, it appears that the color-changes were maximum only when the charge on the surfactant aggregates (i.e., the micellar head-groups) was opposite to that on the dye-ion. [8][9][10][11] Formation of new analytical systems as a result of addition of cationic surfactants to a negatively charged ''colored binary complex'' was suggested by Garcia et al, [12] and in such systems, the addition of (surfactant) micelle might have lead to lowering of pH at which the complex was formed. A detailed knowledge of dye surfactant interactions, which according to Bhowmik et al, [9,13] Mukhopadhyay, [14] and Jana et al [10,15] may be of charge-transfer in nature, should be of help in understanding the mechanism of the surfactant-sensitized color reaction as well as to study the kinetics [16] of the equilibria developed between the species, as proposed.…”

“…[8][9][10][11] Formation of new analytical systems as a result of addition of cationic surfactants to a negatively charged ''colored binary complex'' was suggested by Garcia et al, [12] and in such systems, the addition of (surfactant) micelle might have lead to lowering of pH at which the complex was formed. A detailed knowledge of dye surfactant interactions, which according to Bhowmik et al, [9,13] Mukhopadhyay, [14] and Jana et al [10,15] may be of charge-transfer in nature, should be of help in understanding the mechanism of the surfactant-sensitized color reaction as well as to study the kinetics [16] of the equilibria developed between the species, as proposed. [12,17] One of the key features responsible for the numerous studies of micellar systems is their ability to solubilize and concentrate variety of reagents, in particular, the dye molecules.…”

“…[23,24] Spectroscopic technique is, therefore, commonly used to gain insight about the nature and extent of driving force for the interaction between the polarizable molecules and micelles. [10,22,25] Spectroscopic investigations were also done to study similar interactions between substituted phenols and anilines with surfactants. [16,25] In the present work, we have studied spectrophotometrically, the interaction behavior of p-nitrophenol (NPH) in aqueous media, in the absence and presence of differently charged surfactants (above their CMCs), viz., sodium dodecylsulphate, SDS (anionic), cetylpyridinium chloride, CPC (cationic) and Triton X-100 (nonionic).…”