A small‐angle x‐ray scattering study of alginate solution and its Sol–Gel transition by addition of divalent cations

Zheng‐Yu ‐Y Wang, John W. White, Mikio Konno, Shozaburo Saito, Tsunenori Nozawa

研究成果: Article査読

44 被引用数 (Scopus)

抄録

The small‐angle x‐ray scattering (SAXS) technique has been applied to investigate solution and gel structures of alginate in the absence and presence of two divalent cations: Ca(II) and Cu(II). We have observed a broad maximum in the scattering curve, a characteristic of polyelectrolyte, for the purified alginate sample. The scattering maximum disappears in excess of added simple salt and shifts toward the higher angle region with increasing alginate concentration. Concentration dependence of the position and intensity of the maximum follows power law relations with exponents close to those predicted by theory. Data analysis shows an increase in correlation length ξ and cross‐sectional diameter d0, of polymer chains upon gelation and suggests that a dimeric structure is adopted in the junction zone, consistent with the “egg‐box” model previously proposed. In the Ca(II)–alginate system, the molecular parameters ξ and d0 are found to have good correlation with the macroscopic properties of gelation, such as gel point determined by viscosity measurements. However, for the Cu(II)–alginate system there is no clearly transitional behavior observed in ξ and d0, implying that the junction zone may be replaced by a more uniformly distributed site binding of Cu(II) ions to the carboxyl groups of both mannuronate and guluronate residues, in confirmation of previous 13C‐nmr results. © 1995 John Wiley & Sons, Inc.

本文言語English
ページ(範囲)227-238
ページ数12
ジャーナルBiopolymers
35
2
DOI
出版ステータスPublished - 1995 2

ASJC Scopus subject areas

  • 生物理学
  • 生化学
  • 生体材料
  • 有機化学

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