Measurement and analysis of bath-side interfacial concentration gradients during membrane quenching by phase inversion

A technique based on Fourier transform optical theory has been developed which allows for transient measurements of bath-side interfacial refractive index gradients during the quench step of membrane formation by phase inversion. From examination of individual Fourier components in a diffraction pattern associated with this one-dimensional mass transport process one is able to overcome the temporal and spatial resolution limitations imposed by many of the more traditional optical techniques. A first order expression relating the local refractive index gradient in the quench cell as a function of its measured spatial offset in the Fourier plane was derived for the purpose of determining the interfacial gradient which may be readily converted to individual species (solvent/nonsolvent) concentration gradients. Real-time interfacial gradients were able to be measured anywhere from 2 to 5 seconds after initiation of the quench using this technique. The r.m.s. errors associated with the reported interfacial species concentration gradient values were determined to range between 3% and 7% of the reported values for quench times less than 60 seconds. However, the reproducability of the experiment was shown to be well within these error limits.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Gaides, Gary Edward

Contributors dc:contributor

• McHugh, Anthony J.

• Engineering, Chemical
• Physics, Optics

Statement dc:rights

• Copyright 1992 Gaides, Gary Edward

Language dc:language

eng

Identifier

AAI9215811
(UMI)AAI9215811

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/21789