Rapid coating of polyamide, polyurea, and polythiourea on metal–organic framework surfaces

Well-defined metal–organic framework (MOF)@polymer core–shell composite particles with polyamide, polyurea, and polythiourea as the shell layer have been constructed for the first time using non-solvent-induced surface-aimed polymerization. This surface polymerization method utilizes non-solvent-induced phase separation to concentrate and direct monomers onto MOF particle surfaces, thus completing the coating process in less than 5 min. The generalizability of this method has been demonstrated with different MOFs. Coating MOF particles with any of the three polymers can effectively improve the stability of the MOF in harsh chemical environments. When used for heavy metal removal, polythiourea-coated composite particles (MOF@HDA-PDTC) exhibited a drastically improved Hg(II) removal rate and full utilization of the thione groups for Hg(II) binding compared to their neat polymer counterparts. This highlights the unique benefit of this core–shell architecture for the optimization of diffusion.