Salt-assisted synthesis of mesostructured cellular foams consisting of small primary particles with enhanced hydrothermal stability

Mesoporous silica materials have attracted considerable attention as adsorbents, catalyst supports, and drug delivery carriers due to their large surface area, high pore volume, and controllable pore size. To increase the adsorption or mass transport properties, large pore sized mesoporous silica is highly desired. Here, we demonstrate a new green synthetic route for obtaining salt-assisted mesostructured cellular foams (S-MCFs) using a triblock copolymer as a single structure-directing agent by addition of inorganic salt without using a hydrophobic pore expander. The S-MCF was composed of ∼27 nm cellular pores and 10 nm windows and had distinct pore walls and a cellular structure. S-MCFs showed an enhanced hydrothermal stability compared to other mesocellular silica. In addition, the primary particle size of the S-MCF was 100-300 nm, which is much smaller than that of previously reported mesostructured cellular foams (MCFs) and mesocellular silica foam (MSU-F). The adsorption study using a model protein revealed that small primary particle size in S-MCF is beneficial for mass transfer in a short period of time. Therefore, S-MCF may serve as a potential platform for higher mass transport or adsorption of large molecules with good stability.