Spinodal decomposition and gel structure of quenched poly(γ-benzyl L-glutamate)-toluene solutions

Tatsumi Korenaga, Hidetoshi Oikawa, Hachiro Nakanishi

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Poly(γ-benzyl L-glutamate) (PBLG)-toluene solutions were quenched rapidly from an isotropic phase at elevated temperatures to the coexistence region of the isotropic and liquid crystal (I + LC) phases. The intensity of scattered light, Is, was measured with time after quenching at various scattering angles and quenching temperatures. The average molecular weights, Mw, of PBLG used were 1.0 × 105 (PBLG-10), and 2.3 × 105 (PBLG-23), and the ratios of the actual concentrations to the corresponding crossover concentration φ22* were equal to 1, 5, and 10 in the semidilute regime (hereinafter, PBLG-X-Y: X = 10 or 23; Y corresponds to φ22*). The spinodal decomposition (SD)-like phase separation was suggested to occur at the initial stage of gelation for quenched PBLG-10-1 and PBLG-10-5. In addition, the fractal dimension D and the correlation length ξ at the later stage were determined according to a generalized Zimm relation containing the fractal dimension. For PBLG-10-1, D and ξ were 2.6 and 610 nm, respectively, whereas the same physical quantities for PBLG-10-5 were respectively 2.7 and 250 nm. The former case indicates that the initial (modulated) phase-separation structure induced by the SD-like mechanism was frozen (or pinned), as it is at the later stage, and the latter indicates that the initial structure might grow by superposing a nucleation and growth (NG)-like phase separation on the SD-like process. There was no concrete evidence of SD in the other quenched PBLG samples.

Original languageEnglish
Pages (from-to)487-501
Number of pages15
JournalJournal of Macromolecular Science - Physics
Volume36
Issue number4
DOIs
Publication statusPublished - 1997 Jan 1

Keywords

  • Gelation
  • Light scattering
  • Lyotropic liquid-crystal polymer
  • Poly(γ-benzyl L-glutamate)
  • Rodlike polymer
  • Spinodal decomposition

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Polymers and Plastics
  • Materials Chemistry

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