Measuring and Modelling the Transition Layer during the Dissolution of Grassy Polymer Films.
CORNELL UNIV ITHACA SCHOOL OF CHEMICAL ENGINEERING
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The technique of laser interferometry is now routinely used by the microelectronics industry for the measurement of the dissolution rates of thin polymer films. In addition to the rate of dissolution, laser interferometry can also provide quantitative information on the thickness of the transition layer between the dissolving glassy polymer and the liquid solvent. This paper describes how observed patterns of reflected light intensity may be analyzed to calculate the thickness of the transition layer for polymers that dissolve with little or no swelling. The technique required knowledge of the shape of the concentration profile in the transition layer. However, by assuming various simple model profiles one may obtain a reasonable estimate. Experimental measurements of PMMA films dissolving in methyl ethyl ketone weights M sub w 37,000 to 1,400,000.
- Polymer Chemistry