Small-angle X-ray scattering study of a weak polyelectrolyte in water

Autor: Salvatore S. Stivala, Timothy J. Taylor
Rok vydání: 2003
Předmět:
Zdroj: Journal of Polymer Science Part B: Polymer Physics. 41:1263-1272
ISSN: 1099-0488
0887-6266
DOI: 10.1002/polb.10460
Popis: Small-angle X-ray scattering (SAXS) was used to obtain solution parameters of a weak polyelectrolyte in water in the absence of any additives, such as neutralizing agents or salt. Poly(acrylic acid) (PAA) was used as a weak polyelectrolyte from which SAXS data were obtained in the dilute region of 1-10 mg cm -3 . An intrinsic viscosity of 15.7 dL g -1 was obtained from a plot of reciprocal reduced viscosities versus the concentration. The application of the SAXS data, that is, the contour length (L = 1.97 x 10 4 A), the persistence length (a* = 58.5 A), and the molecular weight (M = 5.9 x 10 5 Da), to the Yamakawa-Fujii equation suggested that PAA in water at 25 °C could be described as a wormlike chain having a cylindrical body of d = 6 A. An end-to-end distance (r = 1.6 x 10 3 A) was calculated from r = 2a*L - 2(a*) 2 . The nonisotropic expansion factor (α = 2.9) was calculated for PAA expanding from the random coil in dioxane at 30 °C Θ) temperature) to the wormlike chain in water at 25 °C.
Databáze: OpenAIRE
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