Laser light scattering study on the structure of a poly(vinylidene fluoride) aggregate in the dilute concentration state

Abstract

By means of laser light scattering, poly(vinylidene fluoride) (PVDF) chains were found to form complex aggregates of very narrow size distribution even at dilute concentrations of good solvents such as propylene carbonate (PC) and gamma-butyrolactone (BL). Almost the same radii of gyration for aggregates in both solvents were obtained as R-G similar to 220 +/- 10 nm. Their static sizes appeared to be concentration-independent as well as temperature-independent at a wide temperature range of 25-160 degreesC in each solvent. As for solvent effects, the static scattering intensities had different scattering patterns especially at high-q regimes and also different hydrodynamic radii were observed as R-H = 380 +/- 10 nm in propylene carbonate and R-H = 320 10 nm in gamma-butyrolactone, respectively. By the introduction of both core-shell structure and core size distribution, the intensity patterns of scattered light and large ratios of R-H/R-G could be explained. The attractive inter-/intramolecular force between four consecutive sequences of head-to-tail CF2 groups was proposed as a driving force, and the amount of head-to-head configuration in PVDF chain seemed to have strong relation with the size of the aggregate.