• Ow, Hooisweng
• Wiesner, Ulrich
• Kamperman, Marleen
• Du, Phong
• Garcia, Carlos B. W.

Abstract

<p>In the present study, a poly(isoprene-block-dimethylamino ethyl methacrylate) diblock copolymer (PI-b-PDMAEMA) is used to structure-direct a polysilazane pre-ceramic polymer, commercially known as Ceraset. To the polymer was added a 2-fold excess in weight of the silazane oligomer (Ceraset). The resulting composite was cast into films, and after cooperative self-assembly of block copolymer and Ceraset, the structure was permanently set in the hexagonal columnar morphology, as evidenced by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Cross-linking of the silazane oligomer was achieved with a radical initiator at 120 °C. Upon heating of the composite to 1500 °C under nitrogen, the structure is preserved and a mesoporous ceramic material is obtained, as demonstrated by SAXS and TEM. The pores are open and accessible, as evidenced by nitrogen sorption/desorption measurements indicating a surface area of about 51 m² g^-1 and a pore diameter of 13 nm, consistent with TEM analysis. These results suggest that the use of block copolymer mesophases may provide a simple, easily controlled pathway for the preparation of various high-temperature ceramic mesostructures.</p>

Topics

• impedance spectroscopy
• pore
• morphology
• surface
• Nitrogen
• composite
• transmission electron microscopy
• ceramic
• copolymer
• block copolymer
• small angle x-ray scattering
• self-assembly