Binary Nanoparticle Superlattices Assembled via Hydrogen Bonding of Block Copolymer Micelles and Colloidal Silica

Abstract

We report the assembly of binary nanoparticle superlattices (BNSLs) composed of amphiphilic block copolymers and colloidal silica, driven by a balance between complementary associative and self-repulsive interactions. In aqueous media, spherical polystyrene-block-poly(ethylene glycol) (PS-b-PEG) micelles co-assemble with similarly sized silica nanoparticles (NPs) via hydrogen bonding between the PEG corona and the silica surface. Concurrently, electrostatic repulsions between the silica NPs regulate coordination numbers to direct long-range structural order. By tuning the pH and ionic strength, we modulate these attractive and repulsive forces to access both NaCl- and CsCl-type lattice symmetries from a single pair of building blocks. This organic–inorganic hybrid platform provides a rare example of BNSL assembly achieved without specific or directional ligands, while maintaining high structural tunability governed by the intrinsic properties of the polymer micelles and silica NPs.