Porous Polymer Monoliths by Emulsion Templating

AbstractPorous polymer monoliths (PPM) are an increasingly important and popular class of materials finding applications in fields such as separation, purification, cell and tissue culturing, storage of liquids and gases, energy storage, structural applications, supports for catalysts and reagents, etc. In contrast to particulate polymer material, monoliths are defined as intractable articles with a homogeneous microstructure. While the method of preparation and the chemical composition largely govern the resulting porous structure, the porous monoliths can be characterized by their pore size profile (micro‐, meso‐, macroporous material), morphology (interconnected or isolated pores, shape of pores), total porosity (pore volume), surface area, and special features, for example, hierarchical porous structure. Meso‐ and micropores mainly contribute to the total surface area of the monolith, whereas macropores, if interconnected, enable the convective mass transfer through the monolith and reduce the overall density of the material. Obtaining PPM with a multimodal pore size distribution is possible via a combination of methods or by a postpolymerization treatment. This is a useful feature allowing the production of materials with tailored porous structure for specific applications where macro‐ and micropores are needed. Generally, the methods for PPM preparation can be divided between templating (two phases are present during the preparation, of which one templates the porosity) and nontemplating (one phase system, eg, phase separation induces pores). This paper introduces the various methods and focuses on the emulsion templating approach. Recently introduced chemistries and combinations of methods as well as new examples of applications are highlighted.