An experimental study on emulsion polymerization for formation of monodisperse particles smaller than 50 nm

• Published in: Colloid and polymer science Vol. 300; no. 4; pp. 397 - 405
• Main Authors: Ishii, Haruyuki, Nakazawa, Hitoshi, Kuwasaki, Naoto, Nagao, Daisuke, Konno, Mikio
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2022; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Coefficient of variation; Comminution; Complex Fluids and Microfluidics; Copolymerization; Emulsion polymerization; Food Science; Nanoparticles; Nanotechnology and Microengineering; Original Contribution; Physical Chemistry; Polydispersity; Polymer Sciences; Polymers; Sodium dodecyl sulfate; Soft and Granular Matter; Special Issue in Memory of Prof. Okubo; Surfactants; Nanoparticles; Emulsion polymerization; Monodisperse
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-022-04942-w

Selections of surfactants and their concentrations are both critical factors in emulsion polymerization for preparation of polymer nanoparticles with low polydispersity (i.e., low coefficient of variation of particle sizes, C V ). Our previous report revealed that employment of an anionic surfactant of sodium octadecyl sulfate (SOS), which has a critical micellization concentration (CMC) much lower than sodium dodecyl sulfate (SDS) commonly used in conventional emulsion polymerization, is very effective for reducing particle sizes without deteriorating their monodispersity. However, the mechanism on formation of small polymer particles with low polydispersity was still not clarified in the previous report. In this report, the number ( N P ) and C V of polymer nanoparticles formed in the polymerization of styrene (St) using SOS were compared with the conventional polymerization using SDS in a wide range of surfactant concentrations including both their CMCs. The comparisons in N P and C V were also performed in copolymerizations with methylmethacrylate (MMA) less hydrophobic than St. These experimental comparisons in N P and C V have rationalized the St/MMA copolymerization using a low-CMC surfactant highly suitable for attaining the formation of nanoparticles with low polydispersity.