Adsorption of polyelectrolyte multilayers on polymer surfaces

Different from the conventional use of charged supports, the assembly of thin coatings by alternate adsorption of oppositely charged polyelectrolytes was realized on a variety of uncharged standard polymers, such as poly(propylene), poly(styrene), poly(methyl methacrylate), and poly(ethylene terephthalate). For the multilayer buildup, the polyelectrolyte pair poly(styrenesulfonate)/poly(choline methacrylate) was used. The quality of the coatings was investigated by UV/vis spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), and X-ray photoelectron spectroscopy (XPS). The multilayer deposition on poly(propylene) (PP) and poly(ethylene terephthalate) (PET) was investigated in detail. On polar poly(ethylene terephthalate) supports, the regular growth of multilayer assemblies is evidenced. In contrast, on less polar supports, in particular on PP, the quality of the poly(styrenesulfonate)/poly(choline methacrylate) multilayers is inferior. However, if a hydrophobically modified poly(choline methacrylate) is employed instead, good quality multilayers are obtained even on PP. Thus, by appropriate choice of the polyelectrolytes used, even very hydrophobic and polar substrates become useful for the alternate adsorption technique