Morphology templating of nanofibrous silica through pH-sensitive gels: in situ and post-diffusion strategies

A pH-sensitive pyridine-based gelator has been found as a flexible and efficient template for the transcription of nanofibrous silica. The morphology and aggregation degree of silica nanofibers and nanotubes (30-60 nm thick, with 3-10 nm inner channels) could be tuned by simply adjusting the pH conditions through the use of in situ'' formed organogels. Interestingly, silica nanotubes with larger inner mesoporous channels (5-35 nm) were obtained by using a post-diffusion'' route instead of the conventional one pot'' or in situ strategy. Preliminary results about the templating of nanofibrous Fe-based hybrid xerogels are also shown, suggesting that this family of gelators could be used to design nanofibers and nanotubes of more complex inorganic phases.