Synthesis of micron-sized polymeric particles in soap-free emulsion polymerization using oil-soluble initiators and electrolytes

Abstract

Soap-free emulsion polymerization of styrene using oil-soluble initiators and electrolytes was investigated to synthesize micron-sized polystyrene particles. It was clear that an oil-soluble initiator, such as AIBN, worked like a water-soluble initiator in soap-free emulsion polymerization of styrene to prepare monodispersed particles with negative charges, probably because of the polarization of the electron-attractive functional groups decomposed from the initiators and the pi electron cloud of benzene in a styrene monomer. The addition of an electrolyte enabled secondary particles to effectively promote hetero-coagulation for particle growth by reduction of an electrical double layer and prevention of self-growth. Changing the concentration and type of electrolyte enabled us to control the size up to 12 μm in soap-free emulsion polymerization of styrene using AIBN. Conventionally, organic solvents and surfactants have been used to prepare micronsized polymeric particles, but this method enabled the synthesis of micron-sized polymeric particles in water using electrolytes without surfactants.

A Surfactant-Free and Shape-Controlled Synthesis of Nonspherical Janus Particles with Thermally Tunable Amphiphilicity

“…The size and number of styrene droplets decreased with increasing polymerization time; eventually, the droplets became invisible from the optical microscopy observation (Figure S5, Supporting Information). After the synthesis, 230 nm PS spherical particles were produced (Figure S6, Supporting Information), as reported elsewhere …”

Size Control of Polymeric Particle in Soap-Free Emulsion Polymerization

“…The monodispersed particles with a diameter of 340 nm and a zeta potential of -44.8 mV were prepared as shown in Fig. 8a and Table 4 (Yamamoto T., 2012). The surface potential was so negative that the polystyrene particles showed good dispersion stability after the polymerization.…”

Facile synthesis of large scale and narrow particle size distribution polymer particles via control particle coagulation during one-step emulsion polymerization

“…Telford et al also prepared polymer particles based on the particle coagulation mechanism [15][16][17]. As mentioned by Koper et al, Yamamoto et al reported that the addition of electrolyte effectively promotes hetero-coagulation and prevents secondary nucleation [18].…”