Research Interests
Statistical physics of macromolecules, phase behavior
(phase stability and thermodynamic ordering) and properties
of complex polymer and biopolymer systems: biocompatible and
water-soluble polymers (their properties and applications
for biomimetics and drug delivery), hydrogen bonded and
associating polymers (reversibly associated living
polymers), polymer/surfactant systems, polymer micelles (at
thermodynamic equilibrium and micellization kinetics),
polyelectrolytes and block copolymers.
Overview of Research
Oligomers functionalized by end groups capable of
reversible association have attracted increasing interest
during recent years. Recent progress in synthesis has
allowed the addition of functional groups to polymer ends
that allows strong but reversible association. Among such
functional groups are the complexes designed for
simultaneous formation of multiple hydrogen bonds or DNA
segments with complementary sequences at different ends.
These oligomers can effectively form long chain polymers
through repeating the association of their functional end
groups (Figure 1). However, unlike the covalent bonding
responsible for regular polymerization process, these bonds
are reversible and temperature dependent. This allows one to
control the extent of association and thus the average
molecular weight of the polymers through the change in
temperature or concentration of donor and acceptor groups in
the solution. This opens up possibilities to construct new
materials with controllable properties taking advantage of
this reversible bonding. In this research, we use a
mean-field approach along with Monte Carlo simulations to
study a system of oligomers with donor and acceptor end
groups to understand the effects such as the energy of
association, concentration, and oligomer length on the
properties of the system.
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Typical configuration for reversibly
associated polymers terminated by one donor and one
acceptor at the ends. red
arrow: linear chain;
blue arrow: ring |
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The concentration dependence of the
overall degree of association for flexible,
semiflexible (flexible spacer, rigid end-groups) and
rigid (rigid spacer and end-groups) |
Current Activity
Reversibly associated polymers have attracted considerable
attention in recent years. This increasing interest is based
on the wealth of unusual properties and phase behavior
exhibited by this class of materials. In particular these
polymers can possess useful physical characteristics for
microelectronics, biomedical applications, coatings and
processing. Among reversibly associated polymers there has
been special interest in biocompatible synthetic polymers,
such as PEO, PAA (polyacrylic acid) and PVP (polyvinylpyrrolidone).
These polymers are water-soluble due to extensive hydrogen
bond formation with water. In addition, PEO inhibits protein
adsorption. These properties make biocompatible polymers the
best candidates for biomedical applications. Polymeric
micelles and other aggregates of biocompatible polymers have
been studied intensively in recent years for drug delivery
purposes. It is our premise that theoretical input to
studies of the stability and efficiency of different drug
carriers can be a great help by allowing researchers to
avoid multiple non-systematic experiments. Progress in
modern synthesis has made possible the creation of a new
sort of associated polymers, hydrogen bonded "living"
polymers. Similar to worm-like surfactant micelles, "living"
hydrogen bonded polymers demonstrate reversible, temperature
dependent rheological properties that find applications in
coatings, hot melt processing and cosmetics. Such reversibly
associated polymers are often used as blend modifiers to
achieve desirable (e.g. rheological) properties. Having this
in mind, a theoretical analysis of the phase and
conformational behavior of "living" polymers is interesting
from both the fundamental and practical point of view.
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Phase Diagram for PEO in water. Solid
curves are the results of theoretical modeling in
comparison with experimental data (symbols) |
Recent Publications
Computer modeling of reversible
association in metallo-supramolecular polymers (with
Chun-Chung Chen), Polymer Preprints 45(1), 391, 2004
Monte Carlo Simulations of Polymer Brushes Formed by
Reversible Head-to-Tail Associating Polymers (with
Chun-Chung Chen), Polymeric Materials: Science and
Engineering 90, 370, 2004
C.-C.Chen, E.E.Dormidontova, Ring-Chain Equilibrium in
Reversibly Associated Polymer Solutions: Monte Carlo
Simulations, Macromolecules, 37 (10), 3905-3917, 2004
E.E.Dormidontova, The Influence of Terminal Groups on Phase
Behavior and Properties of PEO in Aqueous Solutions,
Macromolecules, 37, 7747-7761, 2004
C.-C.Chen, E.E.Dormidontova, Supramolecular Polymer
Formation by Metal-Ligand Complexation: Monte Carlo
Simulations and Analytical Modeling, JACS, published on web
October 20 2004 DOI:
10.1021/ja047521x
“Supramolecular Polymer Formation by Metal-Ligand
Complexation: Monte Carlo Simulations and Analytical
Modeling,” C.-C. Chen and E.E.Dormidontova, JACS,
126, 14972-14978, 2004.
“Architectural and Structural Optimization of Protective
Polymer Layer for Enhanced Targeting,” C.-C.Chen and
E.E.Dormidontova, Langmuir, 21,
5605-5615, 2005.
Recent Presentations
Computer Modeling of Targeting
Enhancement for Gene/Drug Delivery presented at the Rolduc
Polymer Meeting, Kerkrade, The Netherlands, June 27-30, 2004
Elena E. Dormidontova, Micellization
Kinetics in Diblock Copolymer Solutions, University of
Juelich, Germany, July 4, 2004
Chun-Chung Chen, Elena E. Dormidontova, Theoretical and
Computer Modeling of Supramolecular Polymers, MACRO 2004,
40th IUPAC International Symposium on Macromolecules, Paris
4-9, France, 2004
Awards
NSF CAREER Award: “Theoretical
Modeling of Head-to-Tail Reversibly Associated Polymers in
Solution and at Surfaces”, 2004-2009 |
