Sorption processes are of high importance in many industrial applications like producing and processing of polymers, processing and finishing of natural and synthetic fibres, detergency. One topic of the IPF is the investigation of the interactions between solid surfaces and adjacent phases, which are mainly solutions of surfactants consisting of two or more components, polyelectrolytes or proteins in water. The aim of these investigations is to find out the structure of the adsorption layers in wet and dry state and their effect on the properties of the solid surfaces as well as on the influence on technical processes.
Surfactant adsorption: The interactions of solved surfactants and solids are characterized by a strong adsorption due to intermolecular forces and the surface activity, forming aligned mono or multilayers. Two events simultaneously take place when a surfactant solution contacts a dry solid: wetting and adsorption. In some cases also diffusion, especially into a swollen bulk is possible. By the adsorption change the surface properties of the solid like hydrophilicity, hydrophobicity, wettability, electrical charge. The interactions between solids and surfactants in solution are characterized by a series of methods: adsorbed amount, direct forcemeasurements (AFM), in-situ-ATR-FTIR measurements, zeta potential measurements.The structure of the adsorbed layers in dry state is investigated by AFM measurements, XPS and wetting behaviour of water on the solids.
Protein adsorption: Investigations of the adsorption of proteins answer thequestion: What is necessary to make polymersurfaces biocompatible?
Polyelectrolyte adsorption: More information is available here.
Fields of Work
- Investigation of surfactant layers on solids by atomic force microscopy
- Estimation of the adsorbed amount of surfactants on solid surfaces like fibres or powders
- Kinetics and thermodynamics of adsorption processes by calorimetry and ATR-FTIR
- Wetting behaviour of surfactant solutions
- Behaviour of oil in water emulsions on solid surfaces (heterocoalescence)
- Surface properties of the solids after treatment with surfactants
- Titrator (Autochemistry System 960) coupled with surfactant electrode model 93-42 (Orion)
- Total Organic Carbon Analyzer TOC 5000 (Shimadzu)
- Apparatus for determination of the heterocoalescence (self-made)
- Contact angle measurement apparatus
- Device for investigation of rapid wetting: Dynamic Adsorption Tester (Fibro DAT 1100, (Fibro System AB, Sweden)
- AFM Nanoscope III