(Cryo)-TEM Assessment of Droplet Nucleation Efficiency in Hybrid Acrylic/CeO2 Semibatch Miniemulsion Polymerization

Monomer droplet nucleation has been successfully tracked in a seeded semibatch miniemulsion polymerization with miniemulsion feeding. Taking advantage of the marker capacity of CeO 2 nanoparticles two polymerizations were designed. In the first one the seed contained nanoceria while a blank monomer miniemulsion was fed to the reactor and in the second reaction the opposite was done; namely, the seed did not contain any CeO 2 and the miniemulsion fed did. In this way, the presence of the CeO 2 in either seed or nucleated particles allowed tracking the fraction of droplets that efficiently nucleated during miniemulsion feeding. Conventional TEM and cryo-TEM were used to monitor the nucleation efficiency by analyzing separately the particles that did or did not contain CeO 2 nanoparticles.