Density fluctuation correlation length in polymer fluids

MD simulation and PRISM integral equation theory was employed to study collective density correlations in athermal polymer solutions over a wide range of polymer concentrations. At low density the well known behavior that polymer fluids exhibit monotonic exponentially decaying density correlations was found, with the correlation length decreasing with increasing density. However, when the correlation length became comparable with the monomer size, the density correlation function decayed in a oscillator manner, and the correlation length grew with increasing density.