Viscometric study of extremely dilute solutions of two polymers with different molecular weights

Abstract

Abstract The intrinsic viscosity of a polymer A (referred to as guest polymer) in a solvent containing a second polymer B (referred to as host polymer) at constant concentration was found to be lower than the intrinsic viscosity of the same polymer in the pure solvent. This decrease becomes more important as the molecular weight of the host polymer becomes smaller. When the intrinsic viscosity of a low‐molecular‐weight guest polymer is measured in the presence of a high‐molecular‐weight host polymer, no such decrease is observed and the decrease of the dimensions of a guest polymer in the presence of a host polymer of comparable molecular weight, is insignificant. A parameter b AB is introduced characterizing the hydrodynamic interactions between the two polymers in the region of extremely dilute solutions. The values of b AB strongly depend on the difference in the segment densities between the two polymers.