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

doi:10.1021/ma9518518

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 journal › Article › peer-review

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 language	English (US)
Pages (from-to)	4904-4909
Number of pages	6
Journal	Macromolecules
Volume	29
Issue number	14
DOIs	https://doi.org/10.1021/ma9518518
State	Published - Jul 1 1996

All Science Journal Classification (ASJC) codes

Organic Chemistry
Polymers and Plastics
Inorganic Chemistry
Materials Chemistry

Access to Document

10.1021/ma9518518

Cite this

@article{e1ac08319cc0454ba09581c6f90a4eed,

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

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.",

author = "Winters, {Michael A.} and Debenedetti, {Pablo G.} and Condo, {Peter D.} and Maciej Radosz and Schmidt, {Hans Werner}",

year = "1996",

month = jul,

day = "1",

doi = "10.1021/ma9518518",

language = "English (US)",

volume = "29",

pages = "4904--4909",

journal = "Macromolecules",

issn = "0024-9297",

publisher = "American Chemical Society",

number = "14",

}

TY - JOUR

T1 - Effects of compressed carbon dioxide on the phase equilibrium and molecular order of a lyotropic polyamide solution

AU - Winters, Michael A.

AU - Debenedetti, Pablo G.

AU - Condo, Peter D.

AU - Radosz, Maciej

AU - Schmidt, Hans Werner

PY - 1996/7/1

Y1 - 1996/7/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=0030194855&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030194855&partnerID=8YFLogxK

U2 - 10.1021/ma9518518

DO - 10.1021/ma9518518

M3 - Article

AN - SCOPUS:0030194855

SN - 0024-9297

VL - 29

SP - 4904

EP - 4909

JO - Macromolecules

JF - Macromolecules

IS - 14

ER -

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

Abstract

All Science Journal Classification (ASJC) codes

Access to Document

Other files and links

Fingerprint

Cite this