Highly ordered mesoporous silica structures templated by poly(butylene oxide) segment di- and tri-block copolymers

Highly ordered mesoporous silica structures including body-centered cubic (Im (3) over barm), two-dimensional hexagonal (p6mm) and lamellar (L-chi) symmetries have been synthesized by using hydrophobic poly(butylene oxide) moiety diblock and triblock copolymers as structure-directing agents. Under acidic condition, highly ordered, caged cubic mesoporous silica structures (FDU-1, Im (3) over barm) with a large cell parameter (a = 220 Angstrom) can be formed in the presence of triblock poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) (PEO-PBO-PEO) copolymer such as EO39BO47EO39. Calcined FDU-1 has a largest pore size of 120 Angstrom among all known cubic silica mesostructures, a pore volume of 0.77 cm(3)/g, and a BET surface area of 740 m(2)/g. Diblock poly(butylene oxide)-poly (ethylene oxide) (PBO-PEO) copolymer such as BO10EO16 favors to yield highly ordered two-dimensional hexagonal (p6mm) silica mesostructures with a well-uniformed pore size of 60 Angstrom and a large BET surface area of 902 m(2)/g. Lamellar (L-chi) mesostructures can also be obtained when high concentration diblock copolymer is used as the structure-directing agent. The calcined cubic mesostructured silica FDU-1 is hydrothermally stable in boiling water for at least nine days. (C) 2001 Elsevier Science B.V. All rights reserved.