Self-assembly of an interacting binary blend of diblock copolymers in thin films: A potential route to porous materials with reactive nanochannel chemistry

Self-assembly of a binary mixture of poly(styrene)₃₃₆-block- poly(4-vinyl pyridine)₂₅ (PS₃₃₆-b-P4VP₂₅) and poly(ethylene glycol)₁₁₃-block-poly(4-hydroxy styrene)₂₅ (PEG₁₁₃-b-P4HS₂₅) is shown to give rise to a cylindrical morphology in thin films through pyridine/phenol-based hetero-complementary hydrogen bonding interactions between the P4VP and P4HS copolymer segments. Removal of the cylindrical phase (PEG-b-P4HS) allowed access to porous materials having a pore surface decorated with P4VP polymer blocks. These segments could be transformed into cationic polyelectrolytes through quaternization of the pyridine nitrogen atom. The resulting positively charged nanopore surface could recognize negatively charged gold nanoparticles through electrostatic interactions. This work, therefore, outlines the utility of the supramolecular AB/CD type of block copolymer towards preparation of ordered porous thin films carrying a chemically defined channel surface with a large number of reactive sites.