Tunable Compartmentalized Morphologies of Multilayered Dual Responsive Star Block Polyampholytes

Heteroarm star-graft block quarterpolymers [PS_n(P2VP-b-PAA-g-PNIPAM)_n] with pH-sensitive weak polycationic/polyanionic arms and grafted thermoresponsive outer chains are integrated into hydrogen-bonded multilayers with morphologies distinct from those in traditional layer-by-layer assemblies. We discovered that block-specific swelling promotes heterogeneous partitioning of hydrophobic and hydrophilic reservoirs within the interior of the swollen multilayers. The molecular architecture and amphiphilicity balance governs the internal structure and is regulated via solution pH and temperature. In acidic/basic regimes, competing interactions between hydrophobic and ionized blocks favor compartmentalization of water to the hydrophilic pockets near the substrate surface. Heating the assemblies of star block quarterpolymers with high grafting densities above the lower critical solution temperature of the PNIPAM peripheries promotes the aggregation of the functional "soft nanoparticles" into star-like clusters while facilitating global multilayer swelling. These hierarchically structured dual-responsive films possessing tunable charge, porosity, and localized water retention/swelling expand the prospective capabilities of responsive hydrogen-bonded multilayers for separations, targeted encapsulation/release, on-off switching, and ion transport.