Functional polymer particles via thiol-ene and thiol-yne suspension click polymerization

Water-borne thiol-ene and thiol-yne polymer particles were synthesized using several alkene, alkyne, and thiol monomers in suspension thiol-ene and thiol-yne click polymerizations. In particular, we show that thiol-yne suspension polymerizations are possible, and that thermal initiation provides similar results as previously reported photoinitiation of thiol-ene monomers. The particles were analyzed in terms of particle size, glass transition temperature (T-g), and ability to undergo chemical functionalization. Composition and crosslink density clearly impacted the glass transition temperatures, with higher crosslink densities leading to higher T-g values. Polymer particles with excess alkene/alkyne or thiol functionality were also synthesized to examine the influence of monomer stoichiometry on particle size and thermal properties of each system. Functionalization of thiol-ene polymer particles was demonstrated using either the inclusion of an ene-functionalized chromophore during the polymerization, or post-polymerization functionalization using thiol-isocyanate chemistry.