Science at the Edge
Engineering Seminar
January 24th,
2014
11:30 a.m.
Room1400 Biomedical and
Physical Sciences Building
Refreshments served at 11:15
a.m.
Norman Wagner
Alvin B. and Julia O. Stiles
Professor
Chemical & Biomolecular
Engineering
University of Delaware
STF
Technologies LLC
Shear thickening fluids and
their applications
Abstract
Shear thickening colloidal
and/or nanoparticle suspensions are commonly encountered in
chemical and materials processing, and are also the basis of a
technology platform for advanced, field responsive
nanocomposites. In this presentation, I will review some of
the experimental methods and key results concerning the
micromechanics of colloidal suspension rheology.
Micromechanics is the ability to predict the properties of
complex systems from a colloidal or microscopic level
description of the structure and forces. Measurements of the
microstructure commensurate with the viscosity and normal
stress differences in shearing colloidal suspensions provides
an understanding of how to control the viscosity, shear
thinning, and shear thickening rheological behavior typical of
concentrated dispersions. A fundamental understanding of
colloidal suspension rheology and in particular, shear
thickening, has been achieved through a combination of model
system synthesis, rheological, rheo-optical and rheo-small
angle neutron scattering (SANS) measurements, as well as
simulation and theory (Colloidal Suspension Rheology Mewis
and Wagner, Cambridge Univ. Press, 2012).
Shear thickening fluids are
novel field-responsive materials that can be engineered to be
useful nanocomposites for enhanced ballistic and impact
protection, as well as for space applications. I will discuss the
scientific basis of shear thickening and their applications. http://www.ccm.udel.edu/STF/ Although
many applications of concentrated suspensions are hindered by
shear thickening behavior, novel materials have been developed
around shear thickening fluids (STFs). Ballistic, stab and
impact resistant flexible composite materials are synthesized
from colloidal & nanoparticle shear thickening fluids for
applications as protective materials. The rheological
investigations and micromechanical modeling serve as a
framework for the rational design of STF-based materials to
meet specific performance requirements not easily achieved
with more conventional materials, as will be discussed. (Phys. Today, Oct. 2009, p.
27-32)
Bio
Norman
J. Wagner is the Alvin B. and Julia O. Stiles Professor in the
Department of Chemical
&
Biomolecular Engineering at the University of Delaware. He
served as Chair of the Department from 2007-2012, and also the
director of the Center for Neutron Science (www.cns.che.udel.edu).
He leads an active research group in the fields of rheology,
complex fluids, polymers, applied statistical mechanics,
nanotechnology and particle technology. His research focus
areas include the effects of applied flow on the
microstructure and material properties of colloidal
suspensions, polymers, self-assembled surfactant solutions,
and combinations thereof. Prof. He earned his Bachelors degree
from Carnegie Mellon and Doctorate from Princeton University,
was an NSF/NATO Postdoctoral Fellow in Germany, and a
Director’
s
Postdoctoral Fellow at Los Alamos National Lab prior to
joining the University of Delaware in
1991.
He was named a Senior Fulbright Scholar (Konstanz, Germany)
and served as a guest Professor at the ETH, Zurich (1997) and
the University of Rome (2004). He was awarded the Siple Award
in 2002 by the US Army for his development of shear thickening
fluids for novel energy absorbing materials. This
collaborative research with the Army Research Lab is a
major
research and development effort toward creating novel,
protective materials (www.ccm.udel.edu/STF/).
Prof. Wagner has authored or coauthored over 180 scientific
publications and patents and is on the editorial boards of
five international journals. He has co-authored a textbook
(2008) on Mass and Heat Transfer for the Chemical Engineering
series of Cambridge University Press, as well as Colloidal
Suspension Rheology (2011), also Cambridge University Press.
He has developed commercial rheo-optic instruments as well as
novel rheo-SANS instruments for investigating nanoscale and
microscale structure in flowing systems.
More
about Professor Wagner and his research can be found at www.che.udel.edu/wagner.
For further
information please contact Prof. Christina Chan, Department of
Chemical Engineering and Materials Science at [log in to unmask]
Persons with disabilities have the right
to request and receive reasonable accommodation. Please call the
Department of Chemical Engineering and Materials Science at
355-5135 at least one day prior to the seminar; requests
received after this date will be met when possible.