Solvent-Induced Self-Assembly Strategy: Synthesize Mesoporous Hyper-Crosslinking Polymer By Using Amphiphilic Diblock Copolymer

Porous organic polymers,with high porosity and various functional groups,are vibrant materials in biomedicine,catalysis,energy storage,and membrane separation.In the past decade,a series of porous polymers with different structures have been developed,such as covalent organic frameworks?COFs?,porous aromatic frameworks?PAFs?,polymers of intrinsic microporosity?PIM?,conjugated microporous polymers?CMPs?,and hypercrosslinked polymers?HCPs?.Despite the excellent physical and chemical properties of products,the synthetic routes of porous polymers generally require drastic synthetic conditions,such as noble metal catalysts for CMPs,inert atmosphere for PAFs,PIMs,and CMPs,complicated monomers for COFs,which significantly compromise their applications in scale-up and industrial implementation.HCPs,prepared by a succinct Friedel-Crafts reaction,stand out as a kind of practical porous polymer because of the robust and economic synthesis,high porosity,and excellent thermal stability.However,the general nature of C-C coupling process,linking the monomers with strong covalent bonds,generally leads to dense microporous frameworks,which makes it difficult to control mesopores and macropores incorporated in HCPs frameworks.Up to now,few methods have been developed to synthesize HCPs with well-defined nanomorphology and hierarchical pores.To solve these problems,diblock copolymer PEO-b-PS and PS-b-PAA was induced to synthesize hierarchically porous polymers by using solvent-induced self-assembly method.The main achievements are as follows:1.We demonstrate a solvent-induced self-assembly method to synthesize hypercrosslinked hierarchical porous polymers with tunable mesoporous structure and microporous pore wall via a simple Friedel-Crafts reaction.Formaldehyde dimethyl acetal?FDA?/1,2-dichloroethane?DCE?mixed solvents were used as the crosslinker and structure-directing solvent,and poly?ethylene oxide?-b-polystyrene?PEO-b-PS?was used as the template and reaction precursor.Varying the polarity of the reaction system,oleophobic/oleophylic interaction can be controlled to adjust the self-assembly structure of PEO-b-PS from aggregated nanoparticles to hollow spheres then to mesoporous bulk.The mesoporous bulk HCPs exhibit well-defined mesoporous structure and high surface area.2.Hypercrosslinked hollow polymer spheres provide a microenvironment to encapsulate and confine the ultrasmall Pd nanoparticles.The Pd/hHCPs catalyst exhibits excellent catalysis activity in solvent-free aerobic oxidation of aromatic alcohols,aliphatic alcohols,and aromatics hydrocarbons.Pd/hHCPs exhibits a high turnover frequencies?TOF?of 7194 h^-1 in solvent-free oxidation of benzene alcohol with a high conversion of benzene alcohol?63.4%?and a high selectivity?94%?to benzaldehyde.