Research Interests
The
primary focus of my research group is on nonequilibrium behavior
of
complex
fluids (e.g., colloidal suspensions, emulsions, foams,
macromolecular solutions). We are also interested in the
dynamics of granular materials and glass-forming matter.
Complex
nonequilibrium
macroscopic
properties of such systems result from the coupling of the
motion on the macroscopic and microscopic scales. Due
to a relatively large lengthscale and long relaxation
time, the microstructure can be substantially distorted
even by a weak applied stress. Thus, complex fluids and
granular media are often termed soft condensed matter.
Complex fluids and granular
materials are commonly found in nature (e.g., cytoplasm,
milk, sand) and in industrial applications (e.g., drug
delivery systems, cosmetic products).
Nonequilibrium properties of soft materials have
important implications for design of novel
microstructured materials and development of new
particle segregation methods. Studies of soft
condensed matter are also essential for understanding
fundamental processes in living organisms.
Investigations
of nonequilibrium behavior pose many challenging
theoretical problems. Our research
is focused on theoretical and numerical studies, but
we also collaborate with several experimental
investigators.
Research Areas
Microhydrodynamics
More
Microparticles
in
complex fluids interact not only via direct potential
forces but also through hydrodynamic forces mediated by
the suspending fluid. Evaluation of such
forces requires solving Stokes equations in a complex
multiparticle geometry. Our group has developed
efficient algorithms for evaluating such interactions
for systems of spherical particles in free space and in
the presence of a planar wall. Our numerical
procedures are used to study suspension transport in
thin films and in narrow channels, and to investigate
collective particle dynamics in confined suspension
flows.
- Selected Publications:
S. Bhattacharya,
J. Blawzdziewicz,
and E. Wajnryb, Far-field approximation for
hydrodynamic interactions in parallel-wall geometry. J. Comput. Phys. 212,
718, (2006). pdf
S. Bhattacharya, J.
Blawzdziewicz, and E. Wajnryb,
Hydrodynamic interactions of
spherical particles in suspensions confined between two
planar walls. J. Fluid Mech.
541, 263, (2005). pdf
J.
Blawzdziewicz, E. Wajnryb, J. Given, and J. B. Hubbard,
Sharp scalar
and tensor bounds on the hydrodynamic friction of
arbitrarily
shaped
bodies in Stokes flow. Phys.
Fluids, 17, 033602 (2005).
pdf
Numerical
Procedures
Confinement effects in suspensions
More
Our
recent investigations of suspension flows in
parallel-wall channels demonstrated an unexpectedly rich
phenomenology of strongly confined dispersion flows. For
example, we have shown that flow reflected from
confining walls produces transverse particle
displacements resulting in enhanced particle diffusion.
Our recent numerical studies also revealed
hydrodynamically induced pattern formation and
order-disorder transitions in quasi-2D arrays of
microspheres. We are developing theoretical
descriptions of these phenomena.
Selected
Publications:
M. Baron, J. Blawzdziewicz, and
E. Wajnryb, Hydrodynamic crystals: collective
dynamics of regular arrays of spherical particles in a
parallel-wall channel. Phys. Rev. Lett. 100, 174502
(2008). pdf
and auxiliary materials
(movies)
M. Zurita-Gotor,
J. Blawzdziewicz, and E. Wajnryb, Swapping
trajectories: a new wall-induced cross-streamline
particle migration mechanism in a dilute suspension of
spheres. J. Fluid
Mech. 592, 447 (2007). pdf
J. Blawzdziewicz and E. Wajnryb, Phase equilibria in
stratified thin liquid films stabilized by colloidal
particles. Europhys. Lett., 71,
269 (2005). pdf
Nonlinear dynamics of viscous drops
More
Deformable
viscous
drops in external flow can be stabilized either by
capillary forces or by drop rotation resulting from the
vorticity component of the external flow. Our
recent theoretical and numerical investigations
revealed that the interplay between these two
stabilizing mechanisms may result in bistable drop
behavior and transition to chaos in flows with
periodically varying vorticity. We are studying
this interesting nonlinear dynamics and investigating
similar nonlinear phenomena that occur in macromolecules
(e.g., DNA chains) deformed by an external flow.
Other thrusts of our research on drop dynamics include
drop coalescence, emulsion rheology and collective
dynamics of microdrops in microfluidic channels.
Selected
Publications:
P. M. Vlahovska,
J. Blawzdziewicz,
and M. Loewenberg, Small deformation theory for a
surfactant-covered drop in linear flows. J.
Fluid Mech.
624, 293 (2009). pdf
Y.-N.
Young, J. Blawzdziewicz, V. Cristini, and R.
H. Goodman, Hysteretic and chaotic dynamics of viscous
drops in creeping flows with rotation. J.
Fluid Mech.
607, 209 (2008). pdf
M. B. Nemer,
X. Chen,
D. H. Papadopoulos, J. Blawzdziewicz,
and M. Loewenberg, Hindered and accelerated
coalescence of drops in Stokes flow. Phys.
Rev. Lett.
92, 114501 (2004). pdf
Glass transition
As temperature
is decreased or density increased near the glass
transition, the structural relaxation time in glassy
materials increases by many orders of magnitude with
only subtle changes in static correlations.
Understanding the origin of this behavior is one of
the most important outstanding problems in statistical
physics. We are studying this behavior
using concepts of percolation theory, kinetic theory
of dense fluids, and stochastic processes.
Selected Publications:
G. Lois,
J. Blawzdziewicz, and C. S. O'Hern, A percolation
model for glassy dynamics in disordered materials, Phys.
Rev. Lett. 102, 015702 (2009). pdf
Thermoplastic forming of metallic
glasses
Certain liquid metallic
alloys when cooled quickly enough retain
non-crystalline amorphous microstructure. These
alloys, called bulk metallic glasses (BMGs), are
exceptionally strong and have many other unusual
properties. In particular, they can be
thermoplastically formed into a variety of shapes,
with the structure controlled on multiple lenghscales
ranging from macroscale to sub-nanometer scale.
In collaboration with experimental groups of Dr.
Kumar at TTU and Dr.
Schroers at Yale, our group is developing
theoretical descriptions of processes involved in
thermoplastic forming of BMGs, gaining insights into
their nanoscale properties.
Selected
Publications:
G. Kumar, J. Schroers, and
J. Blawzdziewicz, Controllable nanoimprinting of
metallic glasses: effect of pressure and interfacial
properties. Nanotechnol. 24, 105301
(2013). pdf
G. Kumar, P. A. Staffier,
J. Blawzdziewicz, U. D. Schwarz, and J. Schroers,
Ultrasmooth metal surfaces through thermoplastic
forming of metallic glass. Appl. Phys. Lett. 97,
101907 (2010). pdf
Jamming in particulate systems
- Although
granular
media are ubiquitous in nature (e.g., soil, sand,
sediments) and in technological applications
(e.g., powders, grains, pills), static and dynamical
properties of such systems are still poorly
understood. The problems studied by our group
include properties of static particle packings, and
evolution of vibrated or slowly sheared granular
media. Our goal is to develop quantitative descriptions
of such systems, using concepts of equilibrium and
non-equilibrium statistical mechanics.
- Selected
Publications:
G.-J. Gao, J. Blawzdziewicz, C. S.
O'Hern, and M. Shattuck, Experimental Demonstration
of Nonuniform Frequency Distributions of Granular
Packings. Phys. Rev.
E 80,
061304 (2009). pdf
G. Lois, J. Blawzdziewicz, and C. S. O'Hern,
Jamming transition and new percolation universality
classes in particulate systems with attraction. Phys. Rev. Lett. 100,
028001 (2008). pdf
N. Xu, C. O'Hern, and J.
Blawzdziewicz, Random
close packing revisited: Ways to pack frictionless
disks. Phys. Rev. E,
71, 061306 (2005). pdf
Dynamics of biomolecules
Proteins are
biologically active macromolecules composed of a sequence
of amino-acids connected into a long linear chain.
In its biologically functional native state, the chain is
folded into a specific three-dimensional structure.
Our goal is to determine laws governing the folding
process, and determine conditions for reliable folding
into the native state.
Selected
Publications:
G. Lois, J. Blawzdziewicz, and C. S.
O'Hern, Reliable protein folding on complex energy
landscapes: The free energy reaction path. Biophys. J. 95,
2692 (2008). pdf
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Research group
Postdocs
Frank Van
Bussel
Martin Azese
Graduate
students
Alejandro
Bilbao
Amar Patel
Former postdocs
Venkat
Padmanabhan (IIT Kharagpur)
Collaborators at TTU
Sukalyan
Bhattacharya
Golden
Kumar
Kendra
Rumbaugh
Siva Vanapalli
Recent international collaborations
Eligiusz Wajnryb
IPPT PAN Warsaw, Poland
Maria
Ekiel-Jezewska
IPPT PAN Warsaw, Poland
Zbigniew Adamczyk
ICSC PAN,
Krakow, Poland
Francois
Feuillebois
LIMSI-CNRS, France
Jan
Dhont
IFF Juelich Germany
Mauricio
Zurita-Gotor
Abengoa Research,
Spain
ME HOMEPAGE
ME FACULTY
DIRECTORY
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