Physics Colloquium
Friday, September 12, 2003 4 P.M.
E300 Math/Science Center
Rina Tannenbaum
School of Materials Science and Engineering
Georgia Tech University
Nucleation, aggregation and stabilization of metal nanoparticles
Metallic fragments, formed via the decomposition of organometallic
complexes, are highly reactive, generating a nucleation and growth process
that culminates in the formation of nanocrystals. In the absence of
stabilizing molecules, the aggregation process is self-restricting,
but in the presence of a polymer in the reaction medium, the growing
metallic parti-
cles are stabilized by the adsorption of the polymer chains onto their
surfaces, thus lowering their surface energy and creating a barrier
to further aggregation. We have decoupled the kinetic characteristics
of the various steps that comprise the overall nucleation and aggregation
process for various metal nanoclusters. A combination of infrared
and x-ray photoelectron spectroscopies, transmission electron microscopy
and dynamic light scattering is used to identify the individual contribution
of each step to the overall mechanism of metal nanocluster formation.
Refreshments 3:00 P.M. Room E200 Math/Science Center
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