A SANS-Based Evaluation of the Chain Dimension Temperature Dependence of Poly(ethylethylene) under .THETA.-Conditions

The unperturbed chain dimensions of atactic near-monodisperse poly(ethylethylene) were evaluated in different Θ-solvents over the temperature range 10-80 °C. Radii of gyration, measured by small angle neutron scattering (SANS), were found to increase with increasing temperature and led to a value of 0.4 x 10 -3 deg -1 for d In (R 2 ) 0 /dT ; behavior which replicates that seen in the melt state via SANS and thermoelastic measurements. Those findings are contrary to those from intrinsic viscosity measurements.