Probing the reverse micelle environment with a cationic dye by varying oil and water content of micelles

Abstract

In the present work, spectroscopic properties of crystal violet (CV) within water-in-hexane sodium base (2-ethyl hexyl) sulfosuccinate (AOT) reverse micellar environment was investigated as a function of water contents (W = [H2O]/[AOT] = 6,10) in AOT and also function of mass fraction of nanodroplet (MFD = 0.01, 0.04, 0.07, and 0.1) by using UV/visible, and fluorescence techniques. A deviation in the absorption spectra of crystal violet at the high CV concentration (0.002 M) was observed in the AOT reversed micelles. The Quenching in the emission intensity of crystal violet at high CV concentration and blue shift in λ_max of fluorescence of dye was observed as a function of MFD in AOT RMs. At high concentration of dye, molecules of CV can be reside interfacial region but near core of AOT. At low dye concentration, the CV molecules also can be in interfacial region but far from core. The Stokes shift of CV at high concentration decreased with mass fraction of nano-droplet (MFD), whereas at the low CV concentration, its variation often increased. The ratio of ground state to the excited state dipole moment of crystal violet dye also affected by the change in W values and MFD values. The change in dipole moment and stokes shift indicates the different environment around CV for different W and MFD values.

Keywords: AOT; Crystal violet; Nano-droplet; Quenching; Water content.