|Images of the ceramic. TEM analysis of the ceramic cast from THF after pyrolysis to 1,000°C in ammonia, from left to right: bright field image, elemental B map, elemental N map, and high resolution TEM showing short-range order. Click to enlarge.|
GE Global Research, the centralized research organization of the General Electric Company, has developed a promising breakthrough in nanotechnology that provides a direct pathway to making nanoceramic materials from polymeric precursors.
Developing processes and a greater understanding of nano-engineered ceramics could lead to future applications in aviation and energy, where products such as aircraft engines, gas turbines and catalysts could one day achieve new levels of efficiency, reliability and environmental performance.
A cross-disciplinary team led by Dr. Patrick R. L. Malenfant and Dr. Julin Wan made the discovery, which is reported in the January issue of Nature Nanotechnology.
The team developed a very simple synthesis for the polymeric precursor based on a hybrid organic–inorganic block copolymers (BCP) of polynorbornene–decaborane that enables the formation of ordered ceramic nanostructures via self-assembly with tunable morphology and composition.
The resulting material is subsequently pyrolized to yield the desired ceramic, in which the original nanostructure is retained. The unique aspect of the invention is that the desired composition and the ability to form ordered nanostructures are built in. No external template is needed, and the process is simple and robust.
Drawing from recent developments in the literature, we were able to develop a robust synthesis of well-defined block copolymers that doesn’t require stringent atmospheric conditions and that readily assemble into ordered nanostructures upon solvent evaporation. Pyrolysis provides ceramic materials that retain their nanostructure up to 1,400 °C.
Our method enables the synthesis of ordered, high surface area, mesoporous materials that could be explored as non-traditional catalyst supports. We expect the impact of this technology to spread far beyond the materials initially reported due to the powerful combination of synthetic polymer chemistry, polymer physics and ceramics processing.—Dr. Malenfant
The development of nanoceramic materials is a key objective of GE’s Nanotechnology Program at Global Research. Ceramics are extremely heat resistant but brittle materials. However, ceramic materials can be made more durable through nanotechnology. Non-oxide ceramics with increased toughness, combined with their intrinsic heat-resistant properties, could have broad applications for GE’s Aviation and Energy businesses.
Nanostructure engineering in high temperature ceramics is extremely challenging because of the limited number of options available at the high temperatures usually needed to make these materials. Our inorganic block copolymer precursor brings the molecular design of polymers into the realm of nanostructured ceramics. The well-developed science of block copolymer physics can then be utilized to predict and control the formation of a myriad of nanostructures in ceramics. This provides access to many structural motifs that have yet to be explored in these materials.—Dr. Wan
Dr. Malenfant and Dr. Wan point out that while damage tolerant high-temperature ceramics could revolutionize product development in aviation and energy, structural applications are still many years away. More immediate applications could result from the ability to prepare high surface area ceramics that could be exploited in catalysis.
“Self-assembly of an organic–inorganic block copolymer for nano-ordered ceramics”; Patrick R. L. Malenfant, Julin Wan, Seth T. Taylor and Mohan Manoharan; Nature Nanotechnology 2, 43 - 46 (2007) doi:10.1038/nnano.2006.168