Exponentially growing layer-by-layer assembly to fabricate pH-responsive hierarchical nanoporous polymeric film and its superior controlled release performance.

A hierarchical nanoporous polymer film was fabricated through exponentially growing layer-by-layer assembly of weak polyelectrolytes without any template and post-treatment to greatly enhance loading capacity, release time and linear release range with pH-dependence for small molecules over the reported weak polyelectrolyte films, providing great potentials in controlled drug release applications.