Stimulation and Binding Properties of Polyelectrolyte Multilayers Verified by ATR-FTIR Spectroscopy

摘要

We report on the deposition and properties of multilayers composed of reactive' polymers on planar surfaces. As reactive polymers the polycations poly(ethylene-imine), poly(L-lysine) (PLL), poly(allylamime) (PAA) and the polyanions poly(acrylate) (PAC), poly(vinylsulfate), poly(maleate-co-olefines) were used. ATR-FTIR spectroscopy was adopted to study deposition, binding and stimulation properties of polymer multilayers. The binding of charged species of different molecular size such as rhodanide anions and sodium oleate from solution was examined, whereby binding was found to be dependent on the charge of the outermost layer. For these two analytes a selectivity parameter Q, defined as the ratio between the adsorbed amount obtained at the negatively charged and that at the positively charged surface, respectively, was determined. Furthermore, swelling experiments on multilayer assemblies of PLL and PAC exposed to mixtures of ethanol/water (10 - 70% EtOH content) were carried out. Our experiments gave evidence, that the PLL layers showed a more significant increase in density than the PAC layers. The conformation of PLL incorporated into multilayers could be changed by pH variation.