Single-Chain Collapse or Precipitation? Kinetic Diagram of the States of a Polymer Solution

Relaxation of a dilute polymer solution after an abrupt cooling from good- or θ-solvent to poor solvent is considered. Four processes are involved in relaxation, namely, single unknotted chain crumpling, single-chain knotting, interchain aggregation, and interchain entanglement formation. Five different regimes are described depending on the relaxation times of these stages; they are presented on a T−c diagram of the solution. The interpretation of recent experiments of Chu et al.¹ on the kinetic study of a coil-to-globule transition is discussed.