Comparison of dissolution and mutual diffusion coefficients during dissolution of poly(methyl methacrylate) films

✍ Scribed by Uğur, Ş; Pekcan, Ö

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 118 KB
• Volume: 48
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199906)48:6<485::aid-pi175>3.0.co;2-8

✦ Synopsis

Steady state ¯uorescence measurements have been used for studying the dissolution of polymer ®lms. These ®lms are formed by free radical polymerization of methyl methacrylate (MMA) in which pyrene (P y ) was introduced as a ¯uorescence probe. Dissolution of poly(methyl methacrylate) (PMMA) ®lms in chloroform±heptane mixtures were monitored in real-time by the P y ¯uorescence intensity change. Dissolution coef®cients D d of P y molecules were measured during dissolution of PMMA ®lms, and found to be about 10 À6 cm 2 s À1 . After dissolution, ¯uorescence quenching measurements were performed and the Stern±Volmer equation was employed to measure the mutual diffusion coef®cients of heptane (D h ) and P y (D Py ) molecules; these were found to be about 10 À5 cm 2 s À1 .