Emulsion-templated polymers from

Table 2. Synthesis of Emulsion-Templated Polymers from CA HlP s...

Membrane and microfiuidic devices have also been adopted for the precision manufacture of solids from double-emulsion templates. To date, several different types of particles have been successfully produced by incorporating use of various membrane and microfiuidic devices in processes of polymerization, gel formation, crystallization, and molecular or particle self-assembly. Membrane emulsification is more suited to the fabrication of less sophisticated particulates, such as solid lipid micro-Znanoparticles, gel microbeads, coherent polymeric microspheres, and inorganic particles such as silica microparticles. Microfiuidic devices allow more sophisticated particle designs to be created, such as colloidosomes, polymerosomes, 3D colloidal assemblies, asymmetric vesicles, core-shell polymer particles, and bichromal particles. 

Polymer materials can easily be prepared from HIPEs if one or the other (or both) phases of the emulsion contain monomeric species. This process yields a range of products with widely differing properties. Additionally, as the concentrated emulsion acts as a scaffold or template, the microstructure of the resultant material is determined by the emulsion structure immediately prior to polymerisation. 

Figure 5 Templating of porous polymers in carbon dioxide-in-water emulsions. The polymerization takes place in the continuous phase about CO2 droplets. (From Ref. 52.)...

Monodisperse latex spheres of a controlled size can be arranged into three-dimensional arrays and are used as templates to prepare well-defined cavities and structures once the latex sphere template has been removed. These latex spheres are identical to one another in size and shape and are often prepared from colloidal clusters resulting from the aggregation of sol-gel colloids (Section 5.6). The spherical polymer clusters can be fabricated by the slow addition of an aqueous solution into a reservoir of hydrophobic silicone liquid, forming emulsion droplets. This produces a highly structured porous matrix with a well-defined structure upon polymerisation. The size of the droplets is controlled by the concentration of the aqueous latex, the speed at which the suspension is stirred and the ratio between the silicone liquid and latex. As the concentration of the latex spheres increases to its critical concentration, i.e. the concentration at which the colloidal spheres start to order themselves into a close-packed structure, the balls are filtered off and are dried, ready to be used as templates. 

Protonic doping is necessary to convert PAN from an insulator to a conductor (136), and so various dopants such as acid-substituted polymers (143-146) and chiral sulfonic acids (147-149) have been employed. Emulsion polymerization of aniline-afforded PAN particles (150-156) and PAN-silica particles (157,158). Polyaniline nanofibers have been synthesized by template-guided polymerization... 

A variefy of particulate structures have been used as templates for capsule formation. These can be inorganic (carbonates such as CaCOa, MnCOa [1-3] and solid or porous silica nanoparticles [4, 5]), organic (melamine formaldehyde [6]) and polymeric (polystyrene latex [7], mesoglobules, prepared from thermo-responsive polymers [8-10]) materials, emulsion droplets [11-13], bubbles [14], and even red... 

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