Solvent‐Induced Self‐Assembly Strategy to Synthesize Well‐Defined Hierarchically Porous Polymers

Porous polymers with well‐orchestrated nanomorphologies are useful in many fields, but high surface area, hierarchical structure, and ordered pores are difficult to be satisfied in one polymer simultaneously. Herein, a solvent‐induced self‐assembly strategy to synthesize hierarchical porous polymers with tunable morphology, mesoporous structure, and microporous pore wall is reported. The poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) diblock copolymer micelles are cross‐linked via Friedel–Crafts reaction, which is a new way to anchor micelles into porous polymers with well‐defined structure. Varying the polarity of the solvent has a dramatic effect upon the oleophobic/oleophylic interaction, and the self‐assembly structure of PEO‐b‐PS can be tailored from aggregated nanoparticles to hollow spheres even mesoporous bulk. A morphological phase diagram is accomplished to systematically evaluate the influence of the composition of PEO‐b‐PS and the mixed solvent component on the pore structure and morphology of products. The hypercrosslinked hollow polymer spheres provide a confined microenvironment for the in situ reduction of K₂PdCl₄ to ultrasmall Pd nanoparticles, which exhibit excellent catalytic performance in solvent‐free catalytic oxidation of hydrocarbons and alcohols.