Disordered Inverse Photonic Beads Assembled from Linear Block Copolymers

Abstract

Structurally colored colloids, or photonic pigments, offer a sustainable alternative to conventional dyes, yet existing systems are constrained by limited morphologies and complex synthesis. In particular, achieving angle-independent color typically relies on disordered inverse architectures formed from synthetically demanding bottlebrush block copolymers (BCPs), hindering scalability and functional diversity. Here, we report a conceptually distinct strategy to assemble three-dimensional inverse photonic glass microparticles using amphiphilic linear BCPs (poly(styrene-block-4-vinylpyridine), PS-b-P4VP) via an emulsion-templated process. By employing trans-1,2-dichloroethylene to promote interfacial water infiltration, nanoscale aqueous domains form within the organic phase and direct short-range-ordered pore structures. Evaporative solidification arrests these structures into porous photonic beads with angle-independent color. Systematic control of surfactant alkyl chain length and BCP molecular weight enables precise tuning of pore size, shell thickness, and visible-range optical output. Furthermore, post-chemical modification via quaternization of P4VP provides an orthogonal chemical handle to modulate interfacial instability and photonic behavior. This work expands the self-assembly capabilities of linear BCPs and establishes a modular, scalable platform for producing structurally and chemically programmable photonic pigments.