Hollow Microsphere with Mesoporous Shell by Pickering Emulsion Polymerization as a Potential Colloidal Collector for Organic Contaminants in Water

Submicrometer hollow microspheres with mesoporous shells were prepared by a simple one-pot strategy. Colloidal silica particles were used as a particle stabilizer to emulsify the oil phase, which was composed of a polymerizable silicon monomer (TPM) and an inert organic solvent (PEA). The low interfacial tension between colloidal silica particles and TPM helped to form a Pickering emulsion with small droplet sizes. After the polymerization of TPM, the more hydrophobic PEA formed a liquid core, leading to a hollow structure after its removal by evaporation. BET results indicated that the shell of a hollow particle was mesoporous with a specific surface area over 400 m²·g^–1. With PEA as the core and silica as the shell, each resultant hollow particle had a hydrophobic cavity and an amphiphilic surface, thus serving as a good colloidal collector for hydrophobic contaminants in water

Facile Preparation Route toward Speckled Colloids via Seeded Polymerization

A facile method to prepare monodisperse speckled colloids has been developed via one-step seeded polymerization from noncross-linked latex particles. It was found that both cross-linking agents in the added monomer mixture and charged initiation species are essential for the formation of speckles on composite latex particle surface in seeded polymerization. The size and number density of speckles on the surface are tunable by adjusting the concentration of surfactant. A possible mechanism for the formation of such speckled colloids has been proposed based on a series of control experiments. Speckled colloidal particles were used as substrates for the adsorption of tobacco mosaic virus, and a much stronger adsorption was observed compared to smooth particles, implying a potential application of these speckled particles in virus collection and more

Fabrication of a Composite Colloidal Particle with Unusual Janus Structure as a High-Performance Solid Emulsifier

Core–shell particles with cross-linked core and shell were used as seed particles to produce composite Janus particles. It was found that when the shell has distinctly higher cross-linking degree than the core, Janus particles with very unusual structures can be obtained. These particles have two parts, with one part embraced partially or entirely by the other part, adjustable by parameters such as phase ratio or cross-linking degree. On the basis of experimental observations, a possible mechanism for the formation of such unusual Janus particles has been proposed. Janus particles with arms are used to emulsify water–toluene mixtures, forming oil-in-water (O/W) emulsions at very high internal phase content with rather low concentration of particles. Nonspherical emulsion droplets were observed, indicating that these Janus particles are likely to jam at the interface, forming a strong protecting layer to stabilize emulsions