Capsules e.g. useful for selectively complexing and/or decomplexing chemical entities comprise a core of polymerized complexing agent in a shell formed by polycondensation of at least two monomers

Complexing capsules comprise: (a) a core comprising agents that are capable of complexing and/or decomplexing chemical entities and have been functionalized with one or more polymerized monomers; and (b) a shell that is permeable to the chemical entities and comprises a polymer membrane formed by polycondensation of at least two monomers. Independent claims are also included for: (1) production of capsules as above by preparing a solution of a monomer M1, a monomer Mc-grafted complexing agent and optionally a crosslinking agent in a solvent S1, dispersing the solution in an immiscible solvent S2 optionally containing a surfactant, adding a S2-soluble monomer M2 to form capsules by interfacial polycondensation of M1 and M2, and polymerizing and optionally crosslinking Mc; (2) production of complexing capsules by preparing a solution of a monomer M1, a monomer Mc-grafted complexing agent and optionally a crosslinking agent in a solvent S1, dispersing the solution in an immiscible solvent S2 containing a S2-soluble monomer M2 and optionally a surfactant, and simultaneously effecting interfacial polycondensation of M1 and M2 and radical polymerization and optionally crosslinking of Mc. Capsules composites complexantes, caractérisées en ce qu'elles sont essentiellement constituées d'un coeur comprenant des agents aptes à complexer et/ ou décomplexer des entités chimiques, les dits agents étant fonctionnalisés par un ou plusieurs monomères ayant subi une polymérisation; et d'une membrane polymère formée par polycondensation d'au moins deux monomères, la dite membrane renfermant le dit coeur étant perméable aux dites entités chimiques. Procédé de préparation des dîtes capsules et utilisation des capsules composites complexantes comme matériaux de complexation et/ou décomplexation etlou séparation sélective d'entités chimiques.