Cy3 in AOT reverse micelles II. Probing intermicellar interactions using fluorescence correlation spectroscopy.

Area of Science:

• Physical Chemistry
• Supramolecular Chemistry

Background:

• Reverse micelles are water-in-oil microemulsions with applications in nanoreactor design.
• Cyanine-3 (Cy3) is a fluorescent dye used in various biophysical and chemical studies.

Purpose of the Study:

• To investigate the aggregation kinetics of Cy3 dye molecules within AOT reverse micelles.
• To characterize the formation and properties of transient reverse micelle dimers.

Main Methods:

• Dynamic Light Scattering (DLS) to probe bulk solution properties.
• Fluorescence Correlation Spectroscopy (FCS) to analyze individual Cy3-labeled reverse micelles.

Main Results:

• Cy3 molecules form H-aggregate dimers in small AOT reverse micelles (w(0) = 1).
• Cy3 dimerization is coupled with the formation of transient reverse micelle dimers.
• FCS detected transient dimers as prolate ellipsoids, twice the volume of single micelles, not seen by DLS.

Conclusions:

• Cy3 aggregation drives the formation of transient reverse micelle dimers.
• FCS is crucial for observing these transient structures in labeled micelle populations.
• The study elucidates molecular interactions and self-assembly within confined environments.