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Professor of Chemical Engineering
Ph.D., University of California, Berkeley, 1973 Research Interests
A central focus in materials processing is to control the properties of the product through the organization of atomic and molecular aggregates at various length scales originating from atomic to microscopic dimensions. As a subset of this general goal, Aks+search projects aim at designing ceramic matrix composites. Specific applications range from hightemperature ceramic superconductors produced by crystallization of melts at temperatures above 1000°C to the biomimetic processing of nanometer-sized crystals and thin films at temperatures below 100°C. Aksay's past research has led to the development of improved ceramic fabrication processes mainly through the use of colloidal dispersion and consolidation methods. Experimentally and theoretically Aksay addresses fundamental issues on the dispersion of primarily micron-sized powders with polymeric processing aids, the consolidation methods, and microstructure evolution in single- and multi-phase systems. However, for all the answers provided, additional questions indicate a new focus on the length scale of 1 to 100 nm, which is where his group's knowledge of materials synthesis and processing by deliberate design is weakest. Since this is also the range where phenomena associated with atomic and molecular interactions strongly influence the macroscopic properties of materials, the main focus of his group's projects is now on the issues related to the nanodesigning of hierarchically structured ceramic matrix composites with the use of colloidal dispersions and molecular precursors. The concept of hierarchy relates to the fact that macroscopic
properties are not just influenced by the phenomena associated with one length scale but are determined by the accumulation of "substructural" properties at various length scales originating from atomic to microscopic dimensions depending on the structural features of aggregation. In order to design materials with predictable properties, structural development has to be closely controlled at each step during processing, beginning with mixing (at the nanometer scale) and continuing through the densification of the constituent phases (at the micron and larger scales). For instance, in the design of an electrochromic display device as a multifunctional ceramic material, an architectural hierarchy of layering in an electrochromic ceramic with a conductive polymeric
phase becomes essential at micron and larger length scales. Similarly, thin (1μm) films of ceramic ferroelectrics are of interest for numerous microelectronic applications, including nonvolatile memories, piezoelectric microsensors and actuators, optical memories, and dielectric layers. Successful utilization of these ferroelectrics requires not only a fundamental understanding of synthesis and processing at the nanometer scale but also their incorporation into hierarchically arch devices at larger length scales at sufficiently
low enough temperatures so that the direct-gap semiconducting substrates (e.g., GaAs) will not lose their intrinsic properties.
The research projects are all selected to meet this end goal of designing multifunctional ceramics for structural, electronic, and optical applications with a starting point at the atomic and nanometer level. Course
CHE 346: Chemical Engineering Laboratory
Selected Publications
Aksay, I., J. Lahiri, G. Xu, D. Dabbs, N. Yao, and J. Groves.
1997. Porphyrin amphiphiles as templates for the nucleation
of calcium carbonate. J. Am. Chem. Soc. 119:5449.
Sarikaya, M., and I. Aksay, eds. 1995. Biomimetics: Design
and Processing of Materials. Woodbury, NY: AIP Press.
Aksay, I., E. Baer, M. Sarikaya, and D.A. Tirrell, eds. 1992.
Hierarchically structured materials. In Materials Research
Society Symposium Proceedings, Vol. 255. Pittsburgh:
Materials Research Society. Contact Information
A313 E-Quad
Tel 609-258-4393
iaksay@princeton.edu
Category: Chemical
Type: Scientist & Engineers
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