Abstract: The invention relates to polyelectrolyte multilayer coatings and, methods for their preparation and application to substrates to enhance the bioactivity and corrosion protection of the substrates' surface. The invention is particularly suitable for coating substrates employed for medical applications, such as but not limited to medical implant devices for drug and/or biologics delivery in a patient. The substrate has a positive or negative charge. The polyelectrolyte multilayer coatings include at least a first polymer layer and a second polymer layer. The first polymer and second polymer have opposite charges. Each of the polymer layers is individually applied using a layer-by-layer such that an alternating charge multilayer coating is formed.