Highly crosslinked and clickable poly(divinylbenzene) microspheres by type II photoinitiated precipitation polymerization

A new method for the synthesis of highly crosslinked and in situ alkyne functionalized microspheres, by combining type II photoinitiation with precipitation polymerization, is reported. Using a benzophenone-tertiary amine initiation system, the method allows the preparation of functional microspheres at room temperature by UV irradiation in the absence of stabilizers or surfactants of any kind. To demonstrate the presence and accessibility of the alkyne moiety on the polymer particles, fluorescent pyrene groups are attached to the microspheres by copper(I)-catalyzed alkyne-azide cycloaddition click reaction, using 1-azidomethyl pyrene as a model compound. FT-IR, fluorescence spectroscopy, fluorescence microscopy, and scanning electron microscopy are used for characterization of the particles and to monitor the click reaction.