New materials using atom transfer radical polymerization: Microcapsules containing polar core oil

A technique for encapsulation of polar organic solvents using Atom Transfer Radical Polymerization (ATRP) by suspension polymerization is presented. ATRP was used to synthesize crosslinked amphiphilic copolymers based on oil soluble and water soluble comonomers by suspension polymerization. We demonstrate that the slow rate of ATRP crosslinking reactions allows enough time for polymer to migrate in the oil droplets from the interior to the oil-water interface, yielding the thermodynamically favored capsular morphology. This finding is relevant for the encapsulation of polar core oils where the driving force for polymer migration to the oil-water interface is weak. Using less polar xylene as core oil we have shown that polymer architecture can strongly influence its solubility in the oil phase and therefore the morphology of the suspension polymer particles. © 2003 American Chemical Society.