Microstructure of block copolymer/precursor assembly for Si-C-N based nano-ordered ceramics

摘要

Synthesis of polymer-derived ceramics was explored to build nano-order in a Si-C-N system. The polymeric precursor that leads to the desired ceramic composition was self-assembled using block copolymers as structure-directing agents. This paper summarizes our research in the system polybutadiene-block-poly(ethylene oxide) (PB-b-PEO) with a polysilazane as the ceramic precursor. Microstructures ranging from classic lamellar to cylindrical as well as more complicated morphologies are described, and their evolution is shown to vary sensitively with precursor chemistry, loading and heat-treatment history. The ordered nano-scale structure created in the block copolymer/precursor hybrids can be preserved through the pyrolysis process, thereby leading to ordered nanostructures in the final ceramic.