Critical properties of a system of two molten polymers

Abstract

A system of two molten polymers of different lengths N_A and N_B is considered when the interaction is repulsive and leads to a segregation below a critical point T_c. It is known that the critical behaviour is of the 'mean field' type if N_A and N_B are comparable. However if N_B=1 (one of the constituents reduced to a small molecule) it is known that the critical exponents are rather of Ising type. The cross-over between these two behaviours is studied. A Flory-Huggins behaviour is found as soon as the small chains are themselves real polymers (i.e. N_B>>1) independently of the ratio N_A/N_B (>1).