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CPP: Chemische Physik und Polymerphysik

CPP 32: Polymer dynamics

CPP 32.2: Vortrag

Mittwoch, 9. März 2005, 11:30–11:45, TU C130

Long-range correlations in polymer melts — •Hendrik Meyer, Joachim Wittmer, and Jörg Baschnagel — CNRS Institut Charles Sadron, 67083 Strasbourg, France

It is commonly accepted that in concentrated solutions or melts high-molecular weight polymers display random-walk conformational properties without long range memory between subsequent bonds. This has been anticipated already in the 1950s by Flory in his famous "ideality hypothesis". The absence of memory means that the correlation function, C(n), of two bonds separated by n monomers along the chain should exponentially decay with n. This is the standard basis for defining an important experimental measure of chain stiffness, the persistence length.

We present numerical results and theoretical arguments, demonstrating a non-exponential, long ranged decay of C(n) suggesting a profound analogy with the well-known long range velocity correlations in liquids and granular materials we find C(n) to decay algebraically as n^−3/2.

J. Wittmer, H. Meyer, J. Baschnagel, A. Johner, S. Obukhov, L. Mattioni, M. Müller, and A.N. Semenov; Phys. Rev. Lett. 93 (2004), 147801.