Synthesis of poly(methyl methacrylate) nanoparticles via differential microemulsion polymerization

Poly(methyl methacrylate) nanoparticles are synthesized via differential microemulsion polymerization, where the monomers in the reaction system are kept at very low concentrations by continuous differential addition. The effects of various reaction conditions, such as initiator, surfactants, reaction temperature and monomer loadings, on the particle size and molecular weight have been investigated. The effects of initiator and reaction temperature on latex particle numbers and polymer chain numbers within the particles were also investigated. It was observed that the dependence of particle size on reaction temperature and initiator concentration was non-monotonic. The optimized conditions were screened to prepare nanoparticles with the smallest size.

With the increase in the initiator concentration, more active sites could be formed, therefore, the monomer amount that each active site could share becomes less and small particles would result; when initiator concentration is high enough, free radical number one particle could share would increase and then some dead polymer particles could be initiated more than one time resulting in a higher particle size.Figure optionsDownload as PowerPoint slideHighlights
► To reduce particle size, an optimal temperature and initiator amount were found.
► The use of the co-surfactant does not show any benefit, it can be eliminated.
► Monomer/water ratio have effect on particle size if hydrophilic initiator used.
► Higher monomer/water ratio results in smaller particle if hydrophilic initiator used.