Synthesis of monodisperse PS-co-PDMS microspheres by dispersion polymerization

Currently, many challenges exist for developing fabrication or formulation of new materials that are more suitable for nano- or micro-imprinting applications. Among various candidates, poly(dimethylsiloxane) (PDMS) has been extensively applied as mold materials in terms of its advantageous properties. First, the PDMS has low surface energy, which allows it to be released easily from the substrate and be easily transferred to the patter. Second, PDMS has good chemical resistance compared to other polymers due to the high Si-content. At this point, PDMS-based functional nano- or microparticles seems to be a good candidate for direct imprinting applications. In this study, we synthesized the functional microspheres of polystyrene(PS)-co-poly(dimethlysiloxane) (PDMS) exhibiting monodisperse size distribution and low surface energy. A commercially available PDMS macromonomer was employed as a copolymerizing agent for dispersion polymerization of PS in alcohol media. PS-co-PDMS beads with different compositions were synthesized by controlling comonomer ratio. ATR-IR and EDX (energy dispersive X-ray) analysis showed an increasing tendency of PDMS macromonomer in copolymerization and an even distribution of PDMS component over whole volume. Their thermal and surface characteristics were also investigated.