Structure and Morphology Engineering of Hollow Conjugated Microporous Photocatalysts to Boost Photo-Controlled Polymerization at Near-Infrared Wavelengths

Structure and morphology engineering of conjugated microporouspolymers has been considered a promising strategy in the field ofphotopolymerization as it has the potential to promote catalytic efficiencyand address challenges in product contamination. Herein, hollow conjugatedmicroporous photocatalysts (S-hPorIPN MSs) were constructedby Sonogashira-Hagihara polycondensation on the surface ofSiO(2) templates, followed by removal of the SiO2 inner cores and sulfonation of the conjugated shells. Upon the introductionof cyano and sulfonic acid substituents, S-hPorIPNMSs were utilized as an excellent heterogeneous photocatalyst to triggeraqueous RAFT polymerization by a 740 nm near-infrared (NIR) light,affording the preparation of diverse polymers with predictable molecularweight and narrow dispersity. The enhanced penetration capabilitiesprovided by NIR wavelengths allowed the photopolymerization to beconducted through synthetic and biological barriers at faster polymerizationrates in a non-degassed system. Furthermore, high end-group integrity,excellent monomer/chain transfer agent adaptation, and reliable reusabilitywere highlighted on the S-hPorIPN MSs being appliedas photocatalysts for NIR-light-driven polymerization. Taking advantageof the higher surface-area-to-volume ratio and more accessible activesites of S-hPorIPN MSs, we presented the first metal-freeheterogeneous catalyst system capable of achieving faster polymerizationrates through light-proof barriers for aqueous RAFT polymerization.

Automated summary

Hollow conjugated microporous photocatalysts were constructed and utilized as an excellent heterogeneous photocatalyst to trigger aqueous RAFT polymerization by near-infrared light, resulting in the preparation of diverse polymers with predictable molecular weight and narrow dispersity.