Stepwise Incorporation of Nonpolar Polymers within Polyelectrolyte Multilayers

A method for incorporating uncharged, nonpolar polymers, polystyrene and poly[2-(6′-cyano-6′-methyl-heptyloxy)-1,4-phenylene] (CN-PPP), in the stepwise adsorption of polyelectrolyte multilayers is reported. Polystyrene and CN-PPP adsorbed irreversibly from toluene solution onto polyelectrolyte surfaces. The thickness of the adsorbed nonpolar layer was sufficient to cause the wettability of the surface to change from hydrophilic to hydrophobic but only attenuated subsequent polyelectrolyte adsorption and did not terminate it. Ultraviolet− visible spectroscopy provided evidence for the incorporation of the nonpolar polymers within the polyelectrolyte multilayers. The resultant composite film containing poly(styrene) displayed a reduced swellability by water vapor compared to a polyelectrolyte-only film, also consistent with the presence of the hydrophobic polymer within the film.