Hydrogel Engineering and
Imaging Group
Combining expertise in order to
Members:
Thomas
J. Pence, Professor, Mechanical Engineering
Neil
T. Wright, Associate Professor, Mechanical Engineering
Seungik
Baek, Assistant Professor, Mechanical Engineering
L. Guy
Raguin, Assistant Professor, Mechanical Engineering & Adjunct Assistant
Professor, Radiology
Hydrogel
Research
Hydrogels are mixtures of cross-linked long chain
polymers in an aqueous solvent. The cross-links prevent the polymer from
going into solution. The thermal, physical and chemical properties of the
solvent (i.e. temperature, pH, concentration of other chemical species, etc.)
determine the extent to which the solvent interpenetrates the polymer network,
and hence determines the concentration of solvent in the hydrogel.
This solvent concentration determines the natural free volume of the hydrogel.
Thus placing an initially dry polymer in an aqueous solution will lead to
swelling as the solvent diffuses into the polymer, giving rise to the gel.
Changing the thermal, physical or chemical properties of the solvent will
generally lead to a change in the solvent concentration and, in turn, a change
in the amount of swelling. Mechanical loads applied directly to the
hydrogel can also drive solvent in and out of the hydrogel, leading to additional
volume change. To the extent that the loading leads to non-uniform
stress, such additional volume change can also be non-uniform. Since
these processes involve large deformation, the proper framework for describing
the associated macro-scale strain and displacement is that of large (a.k.a.
finite) deformation continuum mechanics. The modern treatment of the
associated equilibrium states of solvent penetration and deformation traces
back to Flory,
Rehner, Treloar, Rivlin and Biot, although the general thermodynamic
framework harks back to Gibbs.
Recent
presentations:
Tom Pence at the
IMA, July 2008
These
interests can be grouped broadly into
Theoretical Modeling
Experimental Mechanics and Gel System
Prototyping
Numerical Simulation
Imaging and Diagnostics