Single Molecule Desorption Studies on Immobilized Nanoclay Particle Surfaces
Ozkaya, B. / Ozcan, O. / Thissen, P. / Grundmeier, G. (2010)
Langmuir 11 (2010), 26, 8155-8160
- Date: 2010
Ozkaya, B. / Ozcan, O. / Thissen, P. / Grundmeier, G. (2010): „Single Molecule Desorption Studies on Immobilized Nanoclay Particle Surfaces“. In: Langmuir 11 (2010), 26, 8155-8160
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FM-based single molecule force spectroscopy was performed on sheetlike inorganic particles of Na-montmorillonite to study the pH-dependent adsorption and desorption behavior of polyelectrolytes in aqueous solutions. Polyallylamine macromolecules were covalently attached on gold-coated AFM cantilevers. Heterogeneous surfaces were formed by immobilizing the nanoclay sheets on mica-stripped ultraflat Au(111) surfaces using aminothiol chemistry.
Because of the constant surface charge of the particles over a wide pH range, polymer line charge density was the only parameter that affected the adsorption and desorption behavior when the ionic concentration was kept constant. Polarization modulation infrared-reflection absorption spectroscopy (PM-IRRAS) was performed on cast polyallylamine films to study the pH-dependent charge density of polyallylamine molecules. A good correlation was found between the line charge density and the adsorption characteristics of polyallylamine.