Synthesis of sub-100 nm PMMA nanoparticles initiated by ammonium persulfate/ascorbic acid in acetone-water mixture

The polymer nanoparticles with size less than 100 nm can be prepared by surfactant-free emulsion polymerization (SFEP) with co-solvent, but it needs to be conducted in high temperature at over the azeotropic point of the solution. In the present study, the redox initiator of ammonium persulfate/ascorbic acid (APS/ASA) was applied to reduce the reaction temperature of SFEP with acetone as co-solvent. The effects of temperature, acetone content, monomer concentration, and initiator on the particle size of poly(methyl methacrylate) (PMMA) were investigated to control average diameter of PMMA nanoparticles (PNs) efficiently. The results showed that the PMMA nanoparticles with 45 nm in diameter and uniform size (PDI < 0.05) can be synthesized conveniently through controlling the ratio of APS/ASA.