Rafael Bras PhD Candidate BS, Massachusetts Institute of Technology Cook Hall 2053A, 1-5934 r-bras at northwestern dot edu

 Osmotic and Structural Properties of Polymer Gels and Brushes

Polymer gels and surface tethered “brushes” are technologically important systems used in everything from adhesives to medical devices. Both systems are analogous to semi-dilute polymer solutions in terms of the importance of osmotic pressure. What differentiates polymer gels and brushes from semi-dilute solutions are the micro-structural details of the system, which are closely coupled to their solution like properties. In this context osmotic pressure becomes a useful quantity to study polymer gels and brushes. By measuring the osmotic pressure of polymer gel systems we are able to monitor microstructural changes. In the case of polymer brush systems the opposite approach is being developed. Microstructural changes are brought about by applied pressure and monitored via x-ray standing wave techniques.

An additional area of interest is the adhesive properties of vocal folds. The ability to speak is directly dependant on the adhesive properties of the vocal folds, yet very little is known about the subject. In collaboration with Prof. Kimberly Fisher of Northwestern’s communication department, many of the techniques used to measure the adhesive properties of polymeric systems are being adapted to directly measure the adhesive properties of live vocal fold tissues harvested from live animal models.