Quaternized samples of poly(4-vinylpyridine) with alkyl side chains of various length (Cs-Cls) and degree of alkylation (ca. 23-97%) were studied by classical film balance. Transfer experiments, ellipsometric characterization and microweighing by quartz crystals show that these polyelectrolyte (PE) systems exhibit a well-defined bilayer formation during compression to areas smaller than the critical area of the monomer unit (so-called collapse), visible as a plateau region in the measured pi/A-isotherms. Time dependent measurements of the monolayer area at constant film pressure can be explained and treated by classical nucleation/growth models. Compressed to the beginning of the plateau region and maintained at constant pressure, the monolayers relax exactly to half of the initial area. These relaxation experiments additionally support the postulated concept of elongated, rodlike structures, facilitating the bilayer formation of the presented PE systems.