title: Influence of ethylene glycol and propylene glycol on polymer diffusion in poly(butyl acrylate-co-methyl methacrylate) latex films.
abstract: We describe fluorescence resonance energy transfer (FRET) experiments carried out to examine the effect of ethylene glycol and propylene glycol on the early stages of polymer diffusion in poly(butyl acrylate-co-methyl methacrylate) latex films. In our approach, we temporarily arrest the drying process of a wet latex film by sealing the film in a previously cooled airtight sample chamber. This arrests propagation of the drying front and suppresses polymer diffusion during the measurements. We then measure donor fluorescence decays from 0.5 mm diameter spots at various locations on the film. From our analysis, we obtain information about the earliest stages of polymer diffusion as the film is still drying. We also investigate the effect of these glycols on polymer diffusion at longer aging times on predried latex films. Ethylene glycol and propylene glycol retard polymer diffusion at early times immediately after the passing of the drying front but enhance the rate of polymer diffusion at later aging times. This behavior is described quantitatively in terms of free-volume theory and the partitioning of the glycols between the aqueous and polymer phases in the film.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Walter F
authors.initials: WF
authors.lastname: Schroeder
authors.forename: Yuanqin
authors.initials: Y
authors.lastname: Liu
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Tomba
authors.forename: Mohsen
authors.initials: M
authors.lastname: Soleimani
authors.forename: Willie
authors.initials: W
authors.lastname: Lau
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Winnik