Adsorption of macromolecules on conducting polymers (English version)
This paper reports on the study of adsorption ofPMMA, a conventional homopolymer, and DNA onto some conducting polypyrroles (PPys) using a variety of techniques. PMMA adsorption was monitored using X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToFSIMS). XPS and ToFSIMS permit to determine the surface composition of PPy surfaces following PMMA adsorption from various solvents, at different concentrations and on three variously doped PPys. Both techniques show that acid-base interactions are important and may govern PMMA adsorption. In addition to these spectroscopies we have used inverse gas chromatography (IGC) to monitor the surface thermodynamic properties of the coated PPy powders and found a solvent effect on the morphology of PMMA coatings. An attempt to check if the same phenomenon is observed on flat surfaces was performed using atomic force microscopy (AFM). In the case of the adsorption of DNA (polyanionicmacromolecule) onto PPy (positively charged polymer chains) using the depletion method in combination with UV spectroscopy, we found that adsorption is one to two orders of magnitude higher than that of conventional polymers onto classical filters. The pH effect was found to be of limited influence on the adsorption isotherms contrary to the effect of PPy dopant which was found to be the major factor governing DNA adsorption.
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