Dynamic hybrid polyion complexes as pH-tunable precursors for prussian blue analog nanoparticles

Hybrid polyion complexes (HPICs), arising from the complexation of double hydrophilic block copolymers with copper(II) ions in aqueous media, constitute versatile precursors for the controlled synthesis of Prussian blue analog nanoparticles upon addition of K₃[Fe(CN)₆]. Particular attention is devoted to polyvinylamine-based copolymers, whose pendant amine groups exhibit a pronounced affinity toward copper ions, an interaction readily modulated through pH adjustment. In the present study, HPICs were generated from poly(N,N-dimethylacrylamide)-b-polyvinylamine and copper(II) ions, and subsequently exploited as nanoreactors for the pH-regulated formation of Prussian blue analog nanoparticles. The controlled release of copper ions from the HPIC matrix, triggered by pH variations, enables precise regulation of their reactivity with potassium ferricyanide. This approach affords access to Prussian blue nanoparticles with well-defined, tunable dimensions, highlighting HPICs as promising platforms for the design of functional nanomaterials.