Functional Monodisperse Microparticles from Thiol-Michael Dispersion Polymerizations

摘要

Step-growth polymers are ubiquitous in materials, however they have not been generally used for the preparation of polymeric colloids. Herein we report a dispersion polymerization method for the realization of step-growth polymeric microparticles. A "click" reaction, namely thiol-Michael addition reaction, is carried out between multi-thiols and multi-acrylates in methanol. Monodispersed microparticles were successfully prepared with tunable diameters ranging from submicron to five microns. The polymerizations proceeded fast with catalytic amount of organic base and quantitative conversion were achieved at ambient conditions. Simply by applying monomers with varied backbones and functionalities, we have prepared both rubbery and glassy microparticles with well-defined narrow glass transition temperatures. With different backbone structures, both hydrolytically stable and degradable particles were achieved. Moreover, off-stoichiometric polymerizations offer in situ functionalities with "clickable" moieties that are ready for further reactions. We have demonstrated that by incorporating particular groups the particles are functionalized with fluorescence, photo-responsiveness, etc. We expect these microparticles will find vast usage in latex materials, composite materials, fluorescent imaging, drug delivery and many other applications.