This award supports theoretical research that will analyze the statistics and thermodynamics of self-associating neutral and charged macromolecules in various environments. In particular, we will determine the structure and phase diagram of solutions of macromolecules with site-specific interactions such as heterogeneous polymers with associating end groups and peptide amphiphile molecules. Heterogeneous molecules with associating end groups form micelles and/or clusters. When their concentration increases the clusters expand over the whole system leading to gel-like structures. The physical properties of these gels will be analyzed as a function of the functionality of the associating groups and the excluded volume of the molecules. We will also analyze the effect of charge on the polymer backbone and of the salt in the environment on the thermodynamics of charged chain solutions with strong site-specific attractions. The association of peptide amphiphile molecules into cylindrical micelles will be analyzed as a function of the concentration and charge of the peptide. We will include hydrogen bonding in the self-associating model and compare its effect on the micelle structure to peptides with dipoles perpendicular to the backbones. Mixtures of peptides amphiphiles of opposite charge will also be analyzed as candidates for cylindrical micelles with specific surface structures driven by the segregation of the This award supports theoretical research that will analyze the statistics and peptides.

Research goals are to generate new models to guide the synthesis and fabrication of new materials involving heterogeneous macromolecules and multicomponent solutions. These systems are capable of self-organizing in a large number of remarkable structures. Our results will aid the design of various experimental systems including non-aqueous thermoreversible gels with controllable adhesive properties, and aqueous thermoreversible gels for drug delivery. Our studies on charge effects on strongly interacting heterogeneous macromolecules, on the other hand, are highly relevant to the understanding of the self-organization of many biological systems. Biological molecules fulfill a wide variety of amazing functions, and the understanding of the relation between their complex structure and their efficiency in performing specific tasks opens the possibility of creating new molecules for innovative applications. Moreover, our studies on peptide amphiphile are motivated by the need of creating new materials for significant medical applications, including nerve repair. We are particularly interested in understanding how different specific interactions, controlled by the synthesis and the environment, influence the properties of the final self-organized material.

Educational goals will generate scientists capable of solving challenging and relevant problems for society. A well-balanced gender and ethnicity is kept in the group to prepare for a new generation of scientists. The group participates in local educational programs at the high school level. The group also interacts with scientists in Mexico and France. %%% This award supports theoretical research that will analyze the statistics and thermodynamics of self-associating neutral and charged macromolecules in various environments. In particular, we will determine the structure and phase diagram of solutions of macromolecules with site-specific interactions such as heterogeneous polymers with associating end groups and peptide amphiphile molecules. The study of these macromolecular solutions will lead to the design of new materials. It will also lead to a better understanding of biological materials, with potential applications in drug delivery, bio-adhesion and nerve repair.

Educational goals will generate scientists capable of solving challenging and relevant problems for society. A well-balanced gender and ethnicity is kept in the group to prepare for a new generation of scientists. The group participates in local educational programs at the high school level. The group also interacts with scientists in Mexico and France. ***

Agency
National Science Foundation (NSF)
Institute
Division of Materials Research (DMR)
Application #
0414446
Program Officer
Daryl W. Hess
Project Start
Project End
Budget Start
2004-07-01
Budget End
2008-06-30
Support Year
Fiscal Year
2004
Total Cost
$300,000
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
DUNS #
City
Evanston
State
IL
Country
United States
Zip Code
60201