Versatile double-templating synthesis route to silica monoliths exhibiting a multimodal hierarchical porosity

Monolithic silica exhibiting a trimodal, hierarchical pore structure has successfully been prepared via sol-gel-processing. Monolithic bodies with interconnected macropores in the micrometer range are a result of controlled phase separation and gelation kinetics, whereas textural mesopores in the 10-20 nm range originate from voids between particles. Furthermore, the particles exhibit internal mesoporosity with pore diameters in the 2-4 nm range originating from supramolecular templating by the surfactant. Poly(ethylene glycol) has been used together with alkylammonium surfactants to control the particle aggregation and internal structure, respectively. The present work sheds light on the mechanism of formation of the complex framework architectures and the application potential of the material.