I. INTRODUCTION Latexes, i.e., dispersions of polymer particles in the 0.05-to 1-µm range, commonly prepared via emulsion polymerization, are widely used for a variety of purposes. In industrial products, they find applications in paints, adhesives, coatings, textiles, and flocculants. In fundamental research, latexes are used as models for studying interparticle interactions as well as size calibration standards. In life science [1-10], the immobilization of biologically active molecules like proteins, enzymes, and antibodies [5-8] on latex particles is useful for enabling detection, quantification, or targeted delivery. Most of the latter applications involve polymer particles bearing functional groups that permit the covalent binding of biomolecules. Polymer microparticles have also been widely used as catalyst and reactant supports since they provide high surface area and can be prepared in a variety of sizes and compositions [11,12]. The activity of latexsupported catalyst depends on the accessibility of the active sites and the reaction rates are usually limited by diffusion.