Synthesis of large-scale, monodisperse latex particles via one-step emulsion polymerization through in situ charge neutralization

Monodisperse sub -200 nm polystyrene nanoparticles were synthesized by a facile one-step emulsion polymerization technology using sodium dodecyl sulfonate (SDS) and 2, 2'- azobis (2-methylpropionamide) dihydrochloride (AIBA) as the surfactant and initiator, respectively. The in situ neutralization between negatively charged surfactant SDS and positively charged AIBA was used to control the primary particle (or swollen micelle) volume and the extent of the particle coagulation. As the oligomeric radicals with cationic AIBA chain ends were captured by anionic swollen micelles, the electrostatic stability of swollen micelles gradually reduced, further promoting the primary particle coagulation. As a result, the initial particle number decreased with the addition of AIBA. The earlier primary particle coagulation not only enlarged the particle size, but also narrowed the particle size distribution of final the latex particles. (C) 2016 Elsevier B.V. All rights reserved.