Regioselectively ordered silica nanotubes by molecular templating

A novel template approach has been developed for the formation of partially ordered silica nanotubes using oligopropylamine functional groups grafted to a rigid cellulose chain for oriented silica deposition on a molecular template. A DPTA cellulose tosylate derivative, which was synthesized and served as a molecular template, represents the catalyst for silica formation, imitating biosilica formation in diatoms. The silica was formed on the cellulose derivative from monomeric precursors such as TEOS and THEOS, while the DPTA residue on the cellulose chain is supposed to favor the oriented polycondensation of ordered silica arrays close to the core of the nanotube. Prolonged reaction times resulted in a regioselectively structured nanotube with an ordered core region and an amorphous mantle. Such nanotubes also might be of specific interest for nanoscale photonic fiber structures.