EQUILIBRIUM DIMENSIONS OF POLYMERS IN QUENCHED DISORDER

The mean square end-to-end distance 〈R2〉 Q of a good solvent solution of a single polymer in the presence of a quenched distribution of point scatterers is calculated to first order in ∈ = 4 - d by renormalization group methods. As the volume of the system becomes infinite, the quenched and annealed averages of the chain dimensions are shown to coincide, and the effect of disorder is seen essentially to generate a renormalized excluded volume interaction that, depending on its strength, leads to chain statistics characteristic of good, theta or marginal solvent conditions. At intermediate values of the volume, the chain is effectively collapsed, but there is no universal asymptotic scaling law that this behavior corresponds to. The size of the chain in this regime is predicted to vary with the square root of the volume, in contrast to the logarithmic variation predicted by Cates and Ball on the basis of mean field arguments. © 1990 American Institute of Physics.