March 4, 2003
Tuesday - 4:30 pm in Swain West 238
Speaker: Dr. Anton Zilman, Weizmann Institute, Israel
Images: image 1 | image 2
Title: Entropic transitions in equilibrium networks
Abstract:
Networks are ubiquitous in physical sciences and living matter. We study theoretically thermodynamics and structure of equilibrium, cross-linked networks. We find that the entropy of the junctions induces an effective attraction that can result in equilibrium between a sol phase and a connected network. A connected network can also be formed in a non-thermodynamic transition upon increase of chain or cross link density, or with decreasing temperature. For rigid rods, we predict the formation of bundles of rods linked by cross links, triggered by the interplay between the translational entropy of the cross-links, and the rotational and translational entropy of the rods. The described transitions are purely entropic in nature, and the ordered phase has actually higher entropy. The results are applied to the explanation of recent experimental findings, including behavior of cross-linked gels of actin.