Effect of Colloidal Stabilizer on the Shape of Polystyrene/Poly(methyl methacrylate) Composite Particles Prepared in Aqueous Medium by the Solvent Evaporation Method

Abstract

Effects of the kind and concentration of stabilizers on the nonspherical shape of polystyrene (PS)/poly(methyl methacrylate) (PMMA) composite particles prepared by release of toluene from PS/PMMA/toluene droplets dispersed in stabilizer aqueous solution were examined. In the case of poly(vinyl alcohol), the surfaces of the obtained particles always had a single dimple. In the case of sodium dodecyl sulfate (SDS), the shapes of the composite particles changed from the dimple, via acorn, to spherical with increasing SDS concentration. It was clarified that the dimple and acorn shapes of the PS/PMMA composite particles were caused by contraction of the PS phase after hardening of the PMMA phase in excentered core-shell and hemisphere morphologies, respectively, which were formed by phase separation during toluene evaporation.

Creation of Functional and Structured Polymer Particles by Self-Organized Precipitation (SORP)

“…After evaporation of the volatile organic solvent, polymer precipitates in emulsion droplets. By using this process, where various nanostructured particles with layered structures are based on the liquid-crystalline phase, micro-and macrophase-separated structures can be prepared from liquid-crystalline polymers, 16 polymer blends, 17 and block copolymers. 18 These precipitationbased particle preparation methods appear promising for the production of nanostructured particles.…”

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems

“…PS particles prepared using PVA had a single deep dimple at the surface; this was attributed to the volume reduction of the HD phase after hardening of the PS phase during toluene evaporation from the droplets. 36 In particular, hemispherical PS particles were obtained when Emulgen 931 was employed. Such particles can be oriented on planar surfaces, with their curved surfaces pointing upward and can act as microlens.…”

Recent Advances in the Emulsion Solvent Evaporation Technique for the Preparation of Nanoparticles and Nanocapsules

“…Indeed, PMMA partially encapsulated PS for high molecular weight polymers whereas the contrary was observed for low molecular weight polymers. Okubo et al investigated the effect of different stabilizers on the morphology of PS/PMMA particles [33]. Particles stabilized with poly(vinyl alcohol) displayed small dimples whereas for SDS acorn and spherical structures with increasing amount of SDS were observed.…”

“…2) [31]. The use of different polymer mixtures or architectures such as polymer blends [19,[33][34][35], statistical copolymers [32], and block copolymers [23,[36][37][38][39][40] is possible. The latter polymer architecture is especially interesting for introducing an additional spatial segregation in nanoparticles to yield new multicompartment structures, such as nanocapsules or polymer particles with two or more phases, which are discussed in more detail below.…”