Effects of compressed carbon dioxide on the phase equilibrium and molecular order of a lyotropic polyamide solution

Michael A. Winters, Pablo G. Debenedetti, Peter D. Condo, Maciej Radosz, Hans Werner Schmidt

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

The effects of compressed carbon dioxide at slightly subcritical temperatures on solutions of a chloro-substituted, para-linked aromatic polyamide (PPTA-Cl) in dimethylacetamide were investigated by depolarized light spectroscopy. Pressurization of isotropic solutions resulted in polymer precipitation at a sharply defined pressure. Pressurization of nematic solutions resulted in an increase in the intensity of scattered light with no evidence of precipitation. A plausible interpretation of this observation is the occurrence of liquid-liquid phase separation into polymer-rich (anisotropic) and polymer-lean (isotropic) phases induced by the compressed carbon dioxide. The results suggest that compressed, near-critical antisolvents can be used to control the degree of anisotropy in liquid-crystalline polymeric systems.

Original languageEnglish (US)
Pages (from-to)4904-4909
Number of pages6
JournalMacromolecules
Volume29
Issue number14
DOIs
StatePublished - Jul 1 1996

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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