Deposition and properties of polyelectrolyte multilayers studied by ATR-FTIR spectroscopy

In-situ ATR-FTIR spectroscopy was adopted to study multilayer assemblies of oppositely charged polyelectrolytes consecutively deposited on plasma treated SiO surface. Two different polyelectrolyte systems were selected for this series of studies in order to address (i) conformational changes in polyelectrolyte multilayers as a response to the external stimuli and (ii) protein adsorption on preformed polyelectrolyte multilayers. The former phenomenon was examined for the polyelectrolyte pair of poly(acrylic acid) (PAA) and poly(l-lysine) (PLL), where PLL provides an advantage of detecting the early adsorption events due to its intense amide I band. Protein adsorption was followed on the multilayer assembly consisting of sodium alginate (SA), cellulose sulfate (CS) and poly(methylene-co-guanidine) (PMCG). These multilayers were used as a model system to simulate protein interactions with the membranes formed by polyelectrolyte complexation.