Polysiloxane-based block copolymers as structure-directing agents in the synthesis of hierarchically organized silica monoliths

In this work the successful application of commercially available, linear PEO-PDMS-PEO block copolymers in the synthesis of hierarchically organized silica monoliths comprising a periodic arrangement of mesopores as well as a well-defined macroporous morphology is presented. All silica monoliths were synthesized via the sol-gel approach with an ethylene glycol-modified silane (EGMS) as precursor. Beyond their use as structure-directing agents, these siloxane surfactants can also be employed as agents to tailor the surface polarity by controlled thermal decomposition of the hydrophilic PEO blocks resulting in a hydrophobic organosiloxane-covered surface.