Monodisperse porous polymer particles in the size range of 10 μm in diameter were prepared via seeded emulsion polymerization. Linear polymer (polystyrene seed) or a mixture of linear polymer and solvent or nonsolvent were used as inert diluents. The pore diameters of these porous polymer particles were on the order of 1000 Å with pore volumes up to 0.9 mL/g and specific surface areas up to 200 m2/g. The physical features of the porous polymer particles depended on the diluent type and the crosslinker content, as well as the molecular weight of polymer seed particles. By varying the molecular weight of the linear polymer, monodisperse porous polymer particles with different pore size distribution could be synthesized. Polymer seed with a low degree of crosslinking instead of linear polymer could also be used to prepare monodisperse porous polymer particles with smaller pore volume and pore size.

Emulsions are multiphasic fluid systems in which liquid droplets are dispersed in another immiscible liquid. The main components of an emulsion are the two liquid phases, typically oil and water, and the emulsifier, which stabilizes the interface between the two liquid phases. Emulsifiers can be a variety of molecules, such as polymers, amphiphilic surfactants, and proteins, and they can also be colloidal particles. Emulsion phase inversion is the process of interconversion between two types of simple emulsions: water-in-oil and oil-in-water emulsions. Phase inversion can be induced by shifting the emulsifier affinity from one phase to the other, which is called transitional phase inversion. It can also be triggered by a change in the water-to-oil ratio of the emulsion, which leads to a process known as catastrophic phase inversion. With recent advances in the stabilization of emulsions using colloidal particles and stimuli-responsive surfactants, numerous novel emulsion systems that undergo emulsion phase inversion by means of various mechanisms have been developed. In this review, we highlight the most recent developments in the field of emulsion phase inversion, focusing on transitional phase inversion, inversion of particle-stabilized emulsions, and flowand shear-induced phase inversion. We also discuss and compare state-of-the-art analytical methods that have been used to detect and understand the emulsion phase inversion process. Our coverage spans from the early concepts of Bancroft's rule through the concept of semiquantitative hydrophilic−lipophilic balance to the more recent theoretical models used to predict and control phase inversion phenomena. We conclude this review by presenting an outlook on the future directions and outstanding problems that warrant future investigations to fully understand the mechanism of emulsion phase inversion at the single-droplet level.

Monodisperse porous styrene‐divinylbenzene copolymer particles were prepared via seeded emulsion polymerization using a mixture of linear polymer (polystyrene seed) and non‐solvent as inert diluent. Experimental evidence was presented to describe the mechanism of formation of porous polymer particles during the copolymerization and solvent extraction stages, in which porosity was a consequence of phase separation in the presence of diluents. Pore structure formation was investigated by changes in copolymerization kinetics, gel content, crosslinking density, particle morphology, surface area, pore volume, and pore size distribution. The process of copolymerization was presented, based on the concepts of production, agglomeration, and fixation of the interior gel microspheres of polymer particles. A portion of linear polymer used as diluent was found to participate in the network structure while the porous matrix was built‐up. The influence of the removal of the linear polymer from the matrix pores during the solvent extraction process on the porous structure was also discussed.

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It has recently been shown that in a broad class of disordered systems oscillatory shear training can embed memories of specific shear protocols in relevant physical parameters such as the yield strain. These shear protocols can be used to change the physical properties of the system and memories of the protocol can later be read out. Here we investigate shear training memories in colloidal gels, which include an attractive interaction and network structure, and discover that such systems can support memories both along and orthogonal to the training flow direction. We use oscillatory shear protocols to set and read out the yield strain memories and confocal microscopy to analyze the rearranging gel structure throughout the shear training. We find that the gel bonds remain largely isotropic in the shear-vorticity plane throughout the training process suggesting that structures formed to support shear along the training shear plane are also able to support shear along the orthogonal plane. Orthogonal memory extends the usefulness of shear memories to more applications and should apply to many other disordered systems as well.