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January 9, 2008


Dr. Patrick Malenfant
GE Global Research
"Ordered Nanoscale Structures in High Temperature Ceramics via Block Copolymer Templating"

Abstract.  Inspired by the fact that exceptional mechanical properties in natural ceramics are due to a hierarchical assembly ranging from the nano to micron scale, a bottom-up approach was explored in an effort to build ordered nanometer scale structures based on high temperature ceramics.  Polymeric precursors that can lead to the desired nonoxide ceramic composition were self-assembled using block copolymers as structure-directing agents.  It will be shown that ordered nanoscale structure in block copolymer/precursor hybrids can be maintained throughout the ceramization process, thereby leading to dense, ordered nano-structures in the pyrolysis product.  We have also recently synthesized a new ceramic forming block copolymer that obviates the need for phase targeting with additives.  The synthesis and self-assembly of these novel polynorbornene-decaborane polymers will be described.  These materials enable the facile synthesis of highly ordered/nanostructured boron based ceramics such as layered boron carbide or mesoporous boron nitride with surface areas as high as 950 m2/g.

Vanderbilt University