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Europhys. Lett.
Volume 63, Number 1, July 2003
Page(s) 139 - 145
Section Interdisciplinary physics and related areas of science and technology
Published online 01 June 2003
DOI: 10.1209/epl/i2003-00489-5
Europhys. Lett., 63 (1) , pp. 139-145 (2003)

Role of cross-links in bundle formation, phase separation and gelation of long filaments

A. G. Zilman and S. A. Safran

Department of Material and Interfaces, Weizmann Institute of Science 76100 Rehovot, Israel

(Received 23 May 2002; accepted in final form 6 May 2003)

We predict the thermodynamic and structural behavior of solutions of self-assembling chains, cross-links and end-cap molecules. We find that at the mean-field level, the entropy of self-assembled 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 the monomer or cross-link density, or with decreasing temperature. For rigid rods, at low temperatures, we predict a transition from an isotropic network to anisotropic bundles of rods linked by cross-links, that is triggered by the interplay between the configurational entropy of the cross-link distribution, and the rotational and translational entropy of the rods.

82.70.Gg - Gels and sols.
05.70.Fh - Phase transitions: general studies.
87.15.-v - Biomolecules: structure and physical properties.

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