SCHOOL OF CHEMICAL, BIOLOGICAL & MATERIALS
ENGINEERING
The University of Oklahoma
Norman, Oklahoma
2004 – 2005 Seminar Series
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DR. THEMIS MATSOUKAS
ASSOCIATE PROFESSOR
DEPARTMENT OF CHEMICA ENGINEERING
PENNSYLVANIA STATE UNIVERSITY
UNIVERSITY PARK, PENNSYLVANIA
Will present a seminar on
“SYNTHESIS OF NANOMATERIALS
IN DUSTY PLASMAS”
In the early 90's scientists in the microelectronics area noticed that process plasmas often produce
particles which tend to remain trapped in the plasma over long periods of time. They called these
systems ”dusty plasmas”' and soon a new research field was born with the goal of understanding the
physics of particle-laden plasmas and the new phenomena that arise from the interaction between
charged particles and plasma. The trapping of particles is now well understood to involve an interplay of
forces whose main component is electrostatic interaction and gravity. While dusty plasmas have excited
the interest of physicists, the chemical engineer sees a "fluidized" bed with the ability to contain and
confine micro and nanoparticles, much smaller than the size that can be fluidized by conventional
methods based on fluid drag. The ability of low-pressure plasmas to trap micron and sub-micron
particles for indefinite periods of time, coupled with the variety of plasma chemistries than can be run in
the plasma, create a unique environment for the synthesis and processing particulate materials and
nanocomposites. We have developed a radio-frequency plasma deposition process that allows us to
deposit thin films, ranging from ultra-low thicknesses of few nm to upwards of 100 nm.
In this talk we will discuss examples of composite materials that can be processed in a dusty plasma. In
the first one, we seed a low-pressure radio-frequency plasma with micron and submicron silica particles
and induce surface deposition of plasma-generated polymers produce by the decomposition of various
hydrocarbon molecules. The thickness of the films is controlled by the deposition time which ranges from
few minutes to two hours. We study the kinetics of this process by monitoring the size of the particles
(core plus coating) as a function of time. In a second example, the deposition process is applied to
metallic nanowires. Finally we discuss particle synthesis in the plasma in the absence of seeds and report
on the formation of nano-and microparticles with a hollow center.
THURSDAY, OCTOBER 21, 2004
COOKIES AND COFFEE -- 3:15 P.M.
SEMINAR -- 3:30 P.M.
SARKEYS ENERGY CENTER, ROOM M-204
THIS IS A REQUIRED SEMINAR FOR CHE 5971