Supercritical Fluid Impregnation of Different Azo-Dyes Into Polymer: In Situ UV/Vis Spectroscopic Study

Author(s)

Truc T. Ngo, University of San DiegoFollow
Charles L. Liotta, Georgia Institute of Technology - Main Campus
Charles A. Eckert, Georgia Institute of Technology - Main Campus
Sergei G. Kazarian, Imperial College School of Medicine

Document Type

Article

Publication Date

2003

Disciplines

Chemical Engineering | Engineering | Polymer Science

Abstract

In situ UV/Vis spectroscopy was used to study supercritical fluid impregnation of azo-dyes with varying functional groups into poly(methyl methacrylate) (PMMA) films. The diffusion and phase behavior of Disperse Orange 25 (DO25) and a dye mixture of Disperse Red 1 and DO25 in PMMA/CO₂ system were studied. Although these azo-dyes are relatively insoluble in supercritical carbon dioxide (scCO₂) (<10⁻⁶ M under conditions of our experiments), the high partition coefficients (≈10⁴–10⁵) between PMMA and scCO₂ phase allow incorporation of ∼1% of these dyes into PMMA matrix. The diffusion of azo-dyes in scCO₂-swollen PMMA film was observed in situ via UV/Vis spectroscopy, and can be tuned simply by changing the CO₂ pressure surrounding the polymer film. This article reports the effects of CO₂ pressures and specific intermolecular interactions on the diffusion rate (or diffusivity) and the partitioning of dye solutes between the fluid phase and the PMMA. It also demonstrates a possibility of enhancing diffusion by a dye mixture that is capable of mutual intermolecular interactions and thus reducing interactions with the polymer matrix.

Digital USD Citation

Ngo, Truc T.; Liotta, Charles L.; Eckert, Charles A.; and Kazarian, Sergei G., "Supercritical Fluid Impregnation of Different Azo-Dyes Into Polymer: In Situ UV/Vis Spectroscopic Study" (2003). School of Engineering: Faculty Scholarship. 27.
https://digital.sandiego.edu/engineering_facpub/27