The electrochemically tailored degradation of polyelectrolyte assemblies holds great promises for the design of inexpensive, easily prepared and precise controlled release systems. However, the conception of such electrochemically responsive platforms for drug or gene delivery requires a detailed understanding of the degradation process of the polyelectrolyte multilayer in which the active species to release are incorporated. To this end, we assess here the influence of an applied electric potential on different polyelectrolyte systems, combining global and local investigation techniques. In situ atomic force microscopy allows us to evidence morphological changes at the nano- and micro-scale, while the investigation at a larger scale by optical waveguide lightmode spectroscopy brings complementary information relating not only to material release into the bulk solution, but also to ion migration and swelling. Weak and highly hydrated poly(L-lysine)/hyaluronic acid assemblies with thicknesses up to several hundreds of nanometre continuously dissolve upon electrochemical trigger. However, stronger and more compact films made of poly(allylamine hydrochloride) and poly(styrene sulfonate) dissolve only if their thickness is of a few tens of nanometres, while thicker films delaminate from the electrode. Additional results obtained with composite films combining both polyelectrolyte systems allow us to present mechanisms based on the continuous formation of protons at the electrode surface due to water electrolysis which fully describe the dissolution and the delamination processes. In addition, the study also reveals a novel approach for the release of free-standing polyelectrolyte membranes, which is of great interest for the development of mechanical sensors, separation membranes, or micromechanical devices.