Colloquium: Ken Sandhage, (Bio)Materials "Alchemy": Shape-Preserving Chemical Conversion of 3-D Biogenic and Synthetic Structures into Catalytic, Sensor, Electronic, and Optical Materials

B. Mifflin Hood Professor, School of Materials Science and Engineering, Georgia Institute of Technology

Abstract

Biological and synthetic self-assembly processes can yield macro-to-microscale structures with complex morphologies and finely-patterned features. For example, intricate three-dimensional (3-D) microscale silica or chitinous structures with patterned nanoscale features are formed by diatoms (single celled algae) or Morpho butterflies, respectively. Synthetic self-assembly approaches have yielded structures with periodically-spaced, micro-to-nanoscale spheres/pores (opal or inverse opal structures) or aligned pore channels (e.g., porous anodic alumina). While such self-assembled structures can be attractive for certain applications, the materials readily formed by these processes may not be preferred for a broader range of uses.

The scalable fabrication of structures with complex 3-D morphologies and with a range of tailorable chemistries may be accomplished by separating the processes for structure formation and for chemical tailoring; that is, solid structures with a desired 3-D morphology may first be self-assembled in a readily-formed chemistry and then converted into a new functional chemistry via a morphology-preserving transformation process. In this presentation, several morphology-preserving fluid/solid (displacive, additive) reaction and conformal (solution-based) layer-by-layer coating approaches will be discussed for generating 3-D replicas of biogenic and synthetic structures comprised of micro-to-nanostructured oxide, metal, or composite materials for catalytic, sensor, optical, and energy harvesting and storage applications.

Bio

Ken H. Sandhage received a B.S. in Metallurgical Engineering with Highest Distinction from Purdue University and a Ph.D. in Ceramics from the Massachusetts Institute of Technology. After working as a Senior Scientist on the reaction processing of optical fibers at Corning, Inc. and high temperature superconductors at American Superconductor Corporation, he joined the Department of Materials Science and Engineering at The Ohio State University (1991).  In 1999-2000, Sandhage was a Humboldt Fellow in the Advanced Ceramics Group at the Technical University of Hamburg-Harburg. In the fall of 2003, Sandhage joined the School of Materials Science and Engineering at the Georgia Institute of Technology (Georgia Tech). Sandhage’s research has largely focused on the fluid/solid reaction processing, and liquid-based conformal deposition, of functional inorganic materials for chemical, sensor, optical, electronic, and refractory applications. This research has yielded several patented processes for fabricating complex-shaped, chemically-tailored materials, including the Biological Assembly and Shape-preserving Inorganic Conversion (BASIC) process and the Displacive Compensation of Porosity (DCP) process. Sandhage is the proposing PI and Co-Director of the BIONIC (Bio-nano-enabled Inorganic/Organic Nanocomposites and Improved Cognition) Air Force Center of Excellence at Georgia Tech. With his students, he has received 5 best paper awards, including the Purdy Award from the American Ceramic Society. He is also a Fellow of the American Ceramic Society, and a member of the National Materials and Manufacturing Board of the National Academies.