Bimodal porous morphology

Agglomeration and bimodal PSDs are vital in view of the conflicting structural requirements for transport and reaction. Structural control during fabrication should thus focus not only on composition but also on effects of agglomeration, porous morphology, and wetting properties of pores. 

Mixed solutions of cationic surfactants and nonionic poly(ethylene glycol) or block copolymers were employed for the synthesis of monolithic trimodal porous silica.[176] Lyotropic mixtures of block copolymers of different lengths with hydrophilic linear PEO chains were also applied to their nanocasting into bimodal micro-mesoporous silica to formulate the dependence of the mesopore sizes and the microporosity on the lengths or sizes of the hydrophobic and the hydrophilic blocks, but the mesostructures were worm-type in morphology and several hundred nanometers or more in size. 

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