Polyelectrolyte multilayers are ultrathin films made from water-soluble polymers: negative and positive polyelectrolytes. If you dip a substrate in these nontoxic polymers alternately, a uniform film builds up - a few nanometers at a time. Our group has been studying these versatile systems for more than a decade and our publications on the subject vary from understanding the fundamentals to modifying their properties and morphology. Multilayers also offer a wide range of applications in the fields of active coatings, selective membranes and biological substrates.
We have established, since their emergence, the presence of intrinsic (polymer-polymer interactions) and extrinsic (polymer-counterions interactions) charges inside these films. We studied their properties with a wide range of techniques available in our lab and department such as Fourier Transform Infrared Spectroscopy (FTIR), Ellipsometry, Atomic Force Microscopy (AFM), radiolabeling of their ionic content, X-ray photoelectron spectroscopy (XPS), electrochemical and electrokinetic measurements. We also used neutron reflectometry at Oak Ridge National Lab to understand their structure.