Mechanism of rhodamine 6G molecular aggregation in montmorillonite colloid

• DOI: 10.2478/s11532-013-0289-1
• Publication Date: 2013-07-18T15:19:26Z
• Authors: Marcel Lofaj; Ivan Valent; Juraj Bujdák
• Keywords: Rhodamine 6G

Abstract Stopped-flow mixing device and visible absorption spectroscopy were used for the analysis of dye rhodamine 6G (R6G) molecular aggregation in colloids based on Na-saturated montmorillonite. Two stages reaction identified: The first stage was very short taking only several seconds, involving adsorption R6G cations their initial surface colloid particles. initially formed J-aggregates exhibited similar spectral properties as monomeric form R6G. In second stage, aggregates converted to sandwich-type H-aggregates absorbing light at significantly lower wavelengths adsorbed monomers. aggregate rearrangement took hours. Monomers, with identical solution, also identified a component complex spectra using principal (PCA) multivariate curve resolution (MCR). Partial bleaching proven. Reaction kinetics followed model considering mechanism aggregation. Data fits stretched-exponential function led determination rate constants, which had been range 10−3−4×10−3s−1.