Structural characteristics of synthesized ordered mesoporous silicas MCM-41, MCM-48 and SBA-15 were studied using XRD, nitrogen adsorption and FTIR methods. Pure water and mixtures with water/benzene and water/chloroform-d adsorbed onto silicas were studied by 1 H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial liquids. Concentrated aqueous suspensions of MCM-48 and SBA-15 were studied by thermally stimulated depolarization current (TSDC) method. Benzene and chloroform−d can displace a portion of water to broad pores from the pore walls and from narrower pores, especially in the case of a large excess of an organic solvent. This process is accompanied by diminution of both interaction energy of water with an adsorbent surface and freezing temperature depression of adsorbed water. The effect of nonpolar benzene on pore water is much stronger than that of weakly polar chloroform-d. Modifications of the Gibbs-Thomson relation to describe the freezing point depression of mixtures of immiscible liquids confined in pores allow us to determine distribution functions of sizes of structures with unfrozen pore water and benzene.

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The ability of β‐cyclodextrin (β‐CD) to form a host–guest complex with relatively hydrophobic molecules such as bisphenol A (BPA), a common wastewater contaminant, has inspired the development of β‐CD‐containing polymers for adsorption applications. For the most part, these polymers are powders, which can limit their applicability. Here, low‐density (~0.1 g cm−3), macroporous monoliths based on unmodified β‐CD were synthesized using emulsion templating. The relatively simple, one‐pot, polyurethane synthesis took place within the external phase of oil‐in‐oil (o/o) high internal phase emulsions (HIPEs) that contained β‐CD and a diisocyanate. The combination of o/o emulsions and a polyurethane reaction enabled the incorporation of relatively high β‐CD contents (up to 63 wt%) and limited the occurrence of the water–isocyanate urea reaction. The resulting open‐cell porous structures varied from an average pore size of 5.0 μm (lower surfactant content) to the typical structure associated with polyHIPEs (higher surfactant content), voids of ~50 μm and interconnecting holes ranging from submicrometer to ~2 μm. The compressive mechanical behaviors of the easily handled monoliths were similar to those of flexible foams, reaching strains of 70% without failure. The BPA adsorption capacities, up to 117.7 mg g−1, may make these monoliths advantageous for adsorption applications.

PolyHIPEs, highly porous polymers synthesized within high internal phase emulsions (HIPEs), emulsions with over 74% internal phase, are of interest for applications such as absorbents, reaction supports, and tissue engineering scaffolds. Typically, the surfactant contents for HIPE stabilization are relatively high, ranging from 20 to 30 wt% of the external phase, with the monomers usually being the remainder. One drawback of using surfactants for these applications is the potential for leachables, necessitating intensive purification processes for their removal. Pickering HIPEs, HIPEs stabilized using amphiphilic solid nanoparticles that spontaneously migrate to the oil-water interface, can be used as an alternative HIPE stabilization strategy. Although nanoparticles can add surface functionality advantageous for the application, polyHIPEs from Pickering HIPEs often lack the interconnecting holes needed for the high permeability required for such applications. This work describes a successful approach for designing an HIPE stabilization system that is based on a combination of nanoparticles and reactive surfactants and that generates the desired surface functionality, an interconnected porous structure, and a low leachable content. Such an approach can extend the applicative utility of such polyHIPEs by circumventing the need for extensive purification.