Tunable Synthesis of Prussian Blue in Exponentially Growing Polyelectrolyte Multilayer Films

Polyelectrolyte multilayer (PEM) Films have become very popular for Surface functionalization and the design of functional architectures such as hollow polyelectrolyte capsules. It is known that properties such as permeability to small ionic solutes are strongly dependent oil the buildup regime of the PEM Films. This permeability call be modified by tuning the ionization degree of the polycations or polyanions. provided the film is made from weak polyelectrolytes. In most previous investigations, this was achieved by playing oil the solution pH either during the Film buildup or by it postbuildup PH modification. Herein we investigate the functionalization of poly(allylamine hydrochloride)/poly(glutamic acid) (PAH/PGA) multilayers by ferrocyanide and Prussian Blue (PB). We demonstrate that dynamic exchange processes between the film and polyelectrolyte solutions containing one of the component polyelectrolyte allow one to modify its Donnan potential and, as I consequence, the amount of ferrocyanide anions able to be retained in the PAH/PGA film. This ability of the film to be a tunable reservoir of ferrocyanide anions is then used to produce a composite film containing PB particles obtained by a single precipitation reaction with it solution containing Fe3+ cations in contact with the Film. The presence of PB in the PEM films then provides magnetic as well its electrochemical properties to the whole architecture.