Dynamic charge density correlation function in weakly charged polyampholyte globules
摘要
We study solutions of statistically neutral polyampholyte chains containing a large fraction of neutral monomers. It is known that, even if the quality of the solvent with respect to the neutral monomers is good, a long chain will collapse into a globule. For weakly charged chains, the interior of this globule is semi-dilute. This paper considers mainly theta-solvents, and we calculate the dynamic charge density correlation function g(k,t) in the interior of the globules, using the quadratic approximation to the Martin-Siggia-Rose generating functional. It is convenient to express the results in terms of dimensionless space and time variables. Let R be the blob size, and let T be the characteristic time scale at the blob level. Define the dimensionless wave vector q = R k, and the dimensionless time s = t/T. We find that for q<1, corresponding to length scales larger than the blob size, the charge density fluctuations relax according to g(q,s) = q^2(1-s^(1/2)) at short times s < 1, and according to g(q,s) = q^2 s^(-1/2) at intermediate times 1 < s < q^(-4). We expect these results to be valid for wave vectors q > 0.1, where entanglements are unimportant.
引用
@article{arxiv.cond-mat/9911296,
title = {Dynamic charge density correlation function in weakly charged polyampholyte globules},
author = {Hindrik Jan Angerman and Eugene Shakhnovich},
journal= {arXiv preprint arXiv:cond-mat/9911296},
year = {2013}
}
备注
12 pages RevTex, 1 figure ps, PACS 61.25.Hq, reason replacement: Expression for dynamic corr. function g(k,t) in old version was incorrect (though expression for Fourier transform g(k,w) was correct, so the major part of the calculation remains.) Also major textual change