Reports: AC6
46748-AC6 Statistical Thermodynamics of Solutions Enclosed in Fluctuating Semipermeable Capsules
In the second year of the project we have concentrated on extending the model for the swelling of particle-encapsulating vesicles, developed mostly in the first year, to account for relevant experimental observations. In parallel, we have begun a new effort to elucidate stability and kinetic issues related to smaller aggregates of amphiphilic molecules.
We established a new contact with the experimental group of Dr. P. Peterlin of the University of Ljubljana, who had developed an optical and image-analysis apparatus for following osmotically swelling vesicles -- ideally suited for comparison with our theory. The collaboration has made it clear that the (small) extensibility of the membrane, previously ignored by our models, is in fact an essential ingredient. We have been working on an extended theory that will include this factor. We hope to come up soon with an improved theory that, supported by those experiments, will provide a simple, unified description for the swelling of vesicles as they approach osmotic lysis.
We have begun working on a new theory for the kinetics of formation of much smaller amphiphilic aggregates (micelles), which are widely used as self-assembled capsules. Unlike previous approaches, which formulated the problem in the framework of reaction kinetics, we employ a free-energy approach that allows treating the various stages of micellization on a single footing.
The achievements of the project so far were presented in talks at four scientific meetings this year: the Israel Physical Society Meeting (12/08), the Israel Chemical Society Meeting (02/09), EU SoftComp Network on Self-Assembly and Biomimetics (03/09), and the American Physical Society Meeting (03/09).
