Electrodeposited nanoporous polypyrrole layers for controlled drug release

Nanostructured layers for controlled drug release are fabricated via direct electrochemical codeposition of polymethylmethacrylate (PMMA) nanospheres (NSs) with polypyrrole (PPy). After codeposition, NSs are etched from the matrix to leave a nanoporous PPy layer. Concentration of NSs in the composite, and the resulting concentration of porosities in the etched layer, is optimized varying deposition current density. A maximum concentration of NSs of about 49% vol., corresponding to a loose random sphere packing, is obtained. Complete dissolution of PMMA NSs upon exposure to a mixture of two solvents is demonstrated. Nanoporous layers are loaded with rhodamine B to check their drug release behavior, which is compared with corresponding bulk PPy layers. Nanoporous coatings covered with a bulk PPy capping layer show a 77% improvement in released Rhodamine B with respect to non-nanostructured PPy.