Professor Igor Sokolov Models the Shaping Mechanism of Nanoporous
Colloidal Silica Particles
Professor Igor Sokolov, of Clarkson University's Department of Chemistry,
is modeling the shaping mechanism of nanoporous colloidal silica
particles. After the discovery of the liquid crystal templating
[1, 2] of hexagonal, cubic and lamellar mesostructured silica, materials
chemistry leaped into the realm of design and synthesis of inorganics
with complex forms. Never before has it been possible to synthesize
inorganics with structural features of a few nanometers and architectures
over such large length scales, up to hundreds of microns. The anticipation
for discovery from mesoscale synthesis is comparable to high Tc
superconductors, porous silicon, conducting organic polymers, fullerenes
and carbon nanotubes. This mesochemistry is inspiring research in
materials science, solid state chemistry, semiconductor physics,
biomimetics and biomaterials. It represents a new way of thinking
about templated synthesis of materials over length scales that have
never been seen before in solid state chemistry.
Figure 5. Variety
of mesoporous shapes: (a) tubes, (b) discoids with protrusions,
(c) "seashell," (d) discoid of sunken shape, (e) "Moebius strip"
shape, (f) spin, (g) fat tube, (h) cone, (i) helix.
a more detailed understanding of supramolecular templating developed,
it became apparent that it also provided a vital and inspirational
link with nature's processing of bio-minerals. Many of these shapes
can be some parts for future nanomachines( Figure 5). Professor
Sokolov is studying the mechanisms of formation of these fascinating
shapes [3, 4]. Together with his graduate student Y.Kievsky, he
is synthesizing the shapes under diverse conditions using different
temperatures, different chemicals, and various mixing conditions.
Figures 6 and 7 show a nice agreement between his theory and
In addition to this modeling work, Professor Sokolov
is involved in the modeling of atomic structures of crystalline
surfaces. He also models the long-range force interaction between
nano/micro particles and various surfaces such as bacterial cell
walls used for bioremediation and wafer surfaces used in semiconductor
Figure 7. 3
D simulation of the discharge of internal stress inside a growing
discoid. Due to differential contraction a flat discoid (a)
evolves into either "sunken" (b) or "protruding" (c) shapes
(reference 3). For example, shape (b) closely resembles the
experimental shape in Figure 5c.
more information about Professor Igor Sokolov and his research,
you may call him at 315-268- 2375 or send email to firstname.lastname@example.org.
1. Kresge C.T., Leonowicz M., Roth W.J., Vartuli
J.C., and Beck J.C., "Ordered Mesoporous Molecular Sieves Synthesized
by a Liquid-Crystal Template Mechanism," Nature, 359, 710
2. Ozin G.A., Kresge C.T., Yang S.M., Yang H., Sokolov I. Yu., and
Coombs N., " Morphokinetics: Growth of Mesoporous Silica Curved
Shapes," Adv. Materials, 11, 52 (1999).
3. Yang M., Sokolov I.Yu, Coombs N., Kresge C.T., and Ozin G.A.,
" Supramolecular Origami: Hollow Helicoids of Mesoporous Silica,"
Adv. Mater., 11, 1427 (1999).
4. Sokolov I.Yu, Yang H., Ozin G.A., and Kresge C.T., " Radial Patterns
in Mesoporous Silica ," Adv. Mater., 11, 636 (1999).
Professor Cetin Cetinkaya is Modeling Acoustic Wave Propagation
in Thin-Layered Structures for Nondestructive Evaluation Applications
Cetin Cetinkaya, of Clarkson University's Department of Mechanical
and Aeronautical Engineering, and his research group have been developing
mathematical models for acoustic wave propagation in thin-layered
structures for nondestructive evaluation. Coating substrates with
thin layers of materials is a common practice in a wide spectrum
of applications. Uncertainties in the deposition process require
measurements and verification of the coating layer materials and
their geometric properties. The characterization of bonding quality
and the determination of the post-deposition bonding material properties
are also of great interest.
modeling work is being directed towards layered structures made
of polymeric materials with an arbitrary number of layers. The typical
layer thicknesses of the structures under investigation are in the
range of 10 mm to 500 mm.
However, the modeling work can be up- and down-scaled for thinner
or thicker layers without any modifications. His modeling efforts
are based on continuum mechanics. Using Navier's equations of motion
and integral transforms, a transfer matrix formulation between the
stress and displacement components on the surfaces of a layer has
been developed. See Figure 8. The main advantage of the transfer
matrix approach is that it allows the development of a consistent
formulation for structures with an arbitrary number of layers. Professor
Cetinkaya's research group has generalized this formulation for
layers with varying material properties and thermoelastic layers.
The varying layer formulation has great potential in evaluating
bonding quality of the interfacial layers. The thermoelastic formulation
has been developed for pulsed laser generated acoustic wave applications.
an experimental program has been developed to enhance the modeling
work. Professor Cetinkaya's research lab has state-of-the-art ultrasonic
testing equipment. An important aspect of the research program is
to verify the mathematical models with experimental studies. He
uses ultrasonics to address the evaluation needs and laser research
to target applications where non-contact operations are required.
more information about Professor Cetin Cetinkaya and his research,
you may call him at 315-268-6514 or send email to email@example.com.