Collapse of a polymer gel induced by complex formation with linear polymers

The thermodynamic theory of swelling and collapse of networks in the solution of linear polymers capable to form complexes with the network chains has been developed. The interaction of components is taken into account in the framework of the Flory-Huggins approximation. It was shown that complex formation in most of the cases leads to the contraction of the network, which can be either continuous or discrete. The influence of the solvent quality for the network and for the complex on the behavior of the network has been studied. If the solvent is poor for complexes the network reswells at high concentration of linear chains in the outer solution. This reswelling is realized as a steep conformation transition.