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

Abstract

Highly ordered mesoporous silica structures including body-centered cubic (Im3m), two-dimensional hexagonal (p6mm) and lamellar (Lα) 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, Im3m) with a large cell parameter (a=220Å) 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 Å among all known cubic silica mesostructures, a pore volume of 0.77 cm3/g, and a BET surface area of 740 m2/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 Å and a large BET surface area of 902 m2/g. Lamellar (Lα) 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.