Solubilization of Congo red into non-ionic bolaform sugar based surfactant: A multi spectroscopic approach

Abstract

Crocin and CR interaction was studied by using UV–visible absorption spectroscopy, dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectroscopy and selected area election diffraction patterns. In an aqueous solution crocin as well as CR self-aggregated independently to form vesicles and truncated squares, respectively. The critical micellar concentration (=2.0 × 10−4 mol/L) of crocin was determined by using CR. Two breaks were observed in the wavelength maxima-[crocin] curves indicating that the vesicles and elongated aggregates exist in the crocin-CR system.TEM images and DLS results indicate that the shape, size, and the size distribution of crocin and CR aggregates depend on the experimental conditions. CR changed the morphology of crocin aggregates in aqueous solution. At high concentration, CR formed complex with crocin (formation constant = 492 mol−1 dm3) through intercalation interactions, whereas, CR encapsulated into the vesicles at lower concentrations.

Keywords

• Bolaform
• Solubilization
• Congo red
• Crocin
• Vesicles