The θ-behaviour of heterogeneous macromolecules

Abstract

A polymer chain consisting of N r segments with a repulsive interaction (binary cluster integral β r) and N a ⪡ N r segments with a stronger, attractive and pairwise saturable interaction ( β a), which is at the averaged θ-point N 2 r β r + N 2 a β a = 0 deviations from the predictions of the two parameter theory: α 2 R − 1 ∼ δz r < 0 and A 2 ∼ δz r > 0 with δz r ∼ β r ( N a N r ) 1 2 . It is shown that the deviations from the universal behaviour are due to the existence of an intermediate length scale ∼ N a N r .