Microwave preparation of narrowly distributed surfactant-free macromolecular nanospheres

The microwave preparation of narrowly distributed colloidal microlatex particles of polymethyl methacrylate (PMMA) and polystyrene (PSt) under normal ambient pressure is reported. There are no any surfactants in the system. The total synthesis time has been reduced from much longer time(conventional method) to less than 1 h(microwave method). The dynamic experimental results indicate that the reaction velocity of PMMA is faster than PSt, which may be due to PMMA absorbing much more microwave radation than PSt. The particle size can be controlled by changing initial recipe. The microparticle volume is plotted versus the concentration of the added monomer at constant concentration of initiator. The linear least-square fitting convincingly shows that the number of the particles is constant. This fact also indicates that the microwave radiation favors the simultaneous nucleation and results in formation of monodisperse system.