Flow injection analysis estimation of diffusion coefficients of pauci- and polydisperse polymers such as polystyrene sulfonates


Authors: Boyle, Buchholz, Mc Carthy, Neal
Subjects: Polymers

Flow injection analysis, often used for determination of diffusion coefficients of nonpolymeric substances, has now been applied to the characterization of pauci- and polydisperse polymers in solution. A relative method was found useful for obtaining moderate quality evaluations of diffusion coefficients and related parameters of polymers. The width at half-height W1/2 of the trace peak is found to be proportional to the number average molecular weight M̄n of pauci- and polydisperse polymers, allowing estimation of M̄r and diffusion coefficients. For sodium polystyrene sulfonates at substantially infinite dilution in 1.0 g L−1 Na2SO4, a linear relation has been observed between the logarithms of the molecular weight M̄n and the mean diffusion coefficient D in the M̄n range of 1000–90,000 g mol−1 or the D range of 30 × 10−7 to 2 × 10−7 cm2 s−1.