| Abstract: | A three-component system containing a polymer (2), a good solvent (1) for that polymer, and a second polymer (3) that is compatible with component (2) and isorefractive with the solvent (1) has been studied by static and dynamic light-scattering methods. In concentrated toluene (1) solutions of poly(vinyl methyl ether) (3), where appreciable chain overlap occurs and excluded-volume effects are reduced, polystyrene (2) may be studied in the dilute-solution limit. Consequently, these light-scattering measurements provide an explicit measure of both thermodynamic and hydrodynamic changes that occur as the total polymer concentration is increased from dilute to concentrated solution. Precise numerical coefficients, correct scaling exponents, the radius of gyration, and the effective hydrodynamic radius can be measured directly along with the observation of long-wave single-chain reptation motions and short-range cooperative motions in semidilute and concentrated solutions. |
