Adsorption, Mobility and Organisation of Organic Molecules at Clay Surfaces Probed by Photophysics and Photochemistry
Abstract
This report contains research information on: Cluster formation of detergents on the clay surface; Adsorption of aromatic compounds on colloidal silica; and Study of the fluorescence decay of molecules adsorbed on surfaces. Cationic detergents adsorb on the clay surface in a non homogeneous way. Methods are Being developed to determine the size of these clusters. Analyzing the fluorescence decay of adsorbed probes with the expression for micellar kinetics seems to be a interesting method. The results obtained by this method will be compared to those obtained by a non-spectroscopic method where one polymerizes the detergent and determines the molecular weight afterwards. Preliminary results give rather small aggregation numbers. Pyrene probe were adsorbed to the surface of two different colloidal silicas. The charge on the silica surface is pH dependent. This dependence can be seen in the spectroscopic behaviour of the adsorbed probe molecules. At lower pH values the silica particles lose their stability and start to gel. this gelation can be followed spectroscopically. A simulation study was performed to establish if it possible to distinguish between a fractal decay as proposed by Klafter and Blumen and other decay functions commonly used on surfaces. As this seems to be the case especially when one analyzes with the aid of the global analysis program one can apply this fractal decay law to experimental data. Keywords: Colloids, methacryoyloxyethylmetyldidodecyl ammonium chloride (ddmemec), Laponite, Quenching, Phosphorus Compounds, Nitrogen compounds.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 15, 1989
- Accession Number
- ADA210125
Entities
Organizations
- Katholieke Universiteit Leuven - Universiteitsarchief