CONFORMATION OF POLY(1,3-DIOXOLANE) IN DILUTE AND SEMIDILUTE AQUEOUS-SOLUTIONS

The conformation of poly(1,3-dioxolane) (PDXL) in aqueous solution was studied by light and neutron scattering, by size-exclusion chromatogr aphy coupled with light scattering, and by viscosimetry. In the absenc e of salt, the solutions contain aggregates which cannot be eliminated either by centrifugation or by filtration. These aggregates result in an excess of scattered intensity, but in an intermediate range of q a vailable in neutron scattering experiments, the behaviors in the dilut e and in the semidilute regimes are those expected for a polymer in a rather good solvent. The scaling law for the concentration dependence of the screening length xi was obtained: xi = 2.29c-0.73. In the prese nce of salt, (0.05 and 0.1 N NaCl), there are no more aggregates altho ugh the value of LCST is very close to that in pure water. The variati on of the radius of gyration with molecular weight was determined as w ell as the temperature dependencies of the second virial coefficient a nd intrinsic viscosity for a given sample.