Effect of nanocavities on the torsional dynamics of thioflavin T in various non-aqueous reverse micelles

Abstract

The photophysics of thioflavin T (ThT) were observed in different non-aqueous reverse micelles by using steady state absorption and emission spectroscopy and time resolved fluorescence spectroscopy. We have used glycerol, ethylene glycol, dimethyl formamide, methanol and acetonitrile as polar solvents to form reverse micelles. In all reverse micelles with increase in w (w = [polar solvent]/[AOT]) the fluorescence quantum yield decreased in a regular way. The time resolved fluorescence study of ThT in different reverse micelles shows the similar trend as like above. We had plotted a calibration curve using the fluorescence quantum yield of ThT in glycerol–methanol mixtures vs. viscosity and from that curve we found that ThT faced a greater microviscosity in glycerol pool of AOT/isooctane/glycerol reverse micelles than in the pure glycerol, even at the highest w value. In all reverse micelles the emission quantum yield of ThT was retarded several times compared to neat solvents. We have found that the fluorescence quantum yield of ThT decreased with gradual increase in polarity by studying the emission properties of ThT in dioxane–water mixtures of different polarity.