Multi-hollow polymer microspheres with enclosed surfaces and compartmentalized voids prepared by seeded swelling polymerization method

Fabrication of Fe3O4@poly(methyl methacrylate-co-glycidyl methacrylate) microspheres via miniemulsion polymerization using porous microspheres as templates for removal of cationic dyes

A novel and simple method was proposed to prepare monodisperse magnetic microspheres with controllable particle sizes and different functionalities.

Porous microspheres of polyaniline, poly(o-toluidine), and poly(m-toluidine) prepared from double emulsions stabilized by toluidine isomers as the single surfactant

HYPOTHESIS

Porous spheres of the conducting polymer polyaniline (PANI) and its derivatives are promising materials for use as functional encapsulants for payload delivery and catalyst supports. Stable water-in-oil-in water (W/O/W) double emulsions can be used to obtain this morphology, but typically require multiple surfactants and stabilizers. A single surfactant system that uses a small amphiphilic molecule is desirable, as it can simplify the method, improve its efficiency, and reduce its cost.

EXPERIMENTS

Granular poly(o-toluidine) (POT) was transformed into porous microspheres when ammonium hydroxide was added to an aqueous acidic dispersion containing the preformed polymer and amphiphilic o-toluidine (OT). The OT, POT, and ammonium hydroxide concentrations were varied to understand the formation mechanism. Conditions were optimized to obtain a narrowed size distribution.

FINDINGS

The rapid change from acidic to alkaline surroundings produces a W/O/W double emulsion from POT and OT over a relatively narrow concentration range. Spheres form when POT dissolves in immiscible OT droplets, and entrapped water droplets form the pores. OT serves as the single amphiphilic surfactant and dissolved POT serves as a hydrophobic co-stabilizer. o-Toluidine, m-toluidine, or p-toluidine could be used as the single surfactant to obtain porous spheres from preformed POT, PANI and poly(m-toluidine).

One-Step Synthesis of Hollow Dimpled Polystyrene Microparticles by Dispersion Polymerization

The design and preparation of hollow nonspherical microparticles are of great significance for their potential applications, but the development of a facile synthetic method using only one production step remains a great challenge. In the current work, a new template-free method based on dispersion polymerization was successfully developed to produce anisotropic hollow polystyrene (PS) microparticles in a single step. In the synthesis, ammonium persulfate (APS) played a critical role in the formation and growth of highly uniform and stable hollow PS microparticles. By varying the concentration of APS and that of the stabilizer used, polyvinylpyrrolidone, we were able to control the average size of the PS particles and their degree of concavity. Based on our results and observations, a plausible mechanism for formation of these unusually shaped PS microparticles was proposed.

One-pot preparation of poly(styrene-co-divinylbenzene)/silver nanoparticles composite microspheres with tunable porosity and their catalytic degradation of methylene blue in aqueous solution

Porous poly(styrene-co-divinylbenzene)/silver nanoparticle composite spheres with tunable porosity were synthesized by seed swelling polymerization method and show a great catalytic degradation of methylene blue within NaBH₄.