Interaction of Azo Dye with Cationic Surfactant Under Different pH Conditions

Abstract

The aggregation induced by Alizarin Yellow R (AYR) in the cationic surfactant, cetyltrimethylammonium bromide (CTAB), was investigated by measuring their UV-visible absorption spectra. Conductance measurements as a function of surfactant concentration below and above the critical micelle concentration (CMC) were studied. CTAB aggregation takes place at the concentration far below its normal CMC in the presence of AYR. Both hydrophobic and electrostatic interactions affect the aggregation process in aqueous solution. The dye effect on the CMC of CTAB was noted by a specific conductivity method as well. AYR-CTAB binding constant (K s ) and water-micelle partition co-efficient (K x ) were quantified with the help of mathematical models employed to determine the partitioning of organic additives in the micellar phase. The number of dye molecules per micelle was estimated at particular CTAB concentrations above CMC, during this study.

Spectral-luminescent properties of pH-sensitive azo fluorophore in complexes with quaternary ammonium disinfectants

“…The peak at 446 nm is probably due to the association of the ion of AHABA with the counterion of a surfactant [40,41], which was later checked by differential absorbance measurements. The peak shoulder around 414-422 nm is probably due to the presence of unbound additive molecule that did not involve in ion pairing association.…”

“…In very acidic medium (pH < 4.0), this azo molecule is in neutral form where the functional groups of carboxylic acid (pK a 5.0) and phenol (pK a 10.0) are not ionized (Scheme 1, [41]). It is in monoanionic form at pH > 5, while it shows dianionic behavior at pH > 10.…”

“…To locate the active sites for electrophilic and nucleophilic attack, the relative polarity and reactivity of AHABA molecule/ion were estimated by molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) energy calculations, since MEP and FMO are handy tools to evaluate the structure-reactivity relationship and chemical stability of the molecules [34][35][36][37][38]. Moreover, to get site-specific affinity and biophysical insight into the molecular distribution of AHABA in colloidal fluid, the spectral behavior of this active azo moiety in association with Quats was analyzed by using excitation and emission spectroscopic measurements given that the ionic surfactants have a profound effect on the spectral behavior of numerous organic molecules [39][40][41][42][43][44][45][46][47].…”

Impact of l-leucine on controlled release of ciprofloxacin through micellar catalyzed channels in aqueous medium

“…3), which shows that the maximum number of CIP molecules is distributed inside the micelle. Although the drug molecules are encapsulated into the micelle cage, they still absorb light more favorably than in the aqueous bulk solution as their chromophores are still oriented in the vicinity of the surface [18,19]. As the micellar interior is non-polar in nature, whereas the aqueous bulk is a polar one, drug molecules, being amphiphilic in nature, prefer to reside inside the micelle near the polar surface.…”

Physicochemical investigation of antibacterial Moxifloxacin interacting with quaternary ammonium disinfectants

“…3)indicate the maximum allocation of additive molecules within the micelle interior. Though, the additive moieties are encapsulated into the micelles cage, their chromophores are still oriented in the vicinity of the surface, which eventually leads to the favorable absorption of light more near to the surface than in the bulk aqueous solution[46,47]. Since, the micellar interior is a nonpolar moiety when compared to the polar bulk aqueous solution, hence, the MOF molecules, being amphiphilic in nature, prefer to reside inside micelle near the polar surface.…”