SOLVENT RETENTION IN ULTRA THIN POLYMER FILMS
J. García Turiel and B. Jérôme
Department of Chemical Engineering , University of Amsterdam
Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
In organic coatings of rigid substrates the presence of guest molecules (e.g. solvent molecules) is known to influence the properties of the material
1
. In this work we try to determinate the solvent retention in ultra thin polymer films (D≤200nm) by Gas
Chromatography. This research will be applied to study the adsorption and desorption mechanism of molecules in ultra thin polymer films.
For this experiments the system we studied was Polystyrene films prepared by spincoating from solutions of Polystyrene in Toluene
2
. The dependence of the solvent retention with the film thickness, time and temperature was analyzed to determinate not only the amount of solvent but also where it could be retained in the film.
Results showed that while the annealing conditions do not play a strong influence on the retained solvent, the film thickness does. Relative values showed that the solvent retention remains constant with the film thickness, deviations from bulk behavior are shown for film thickness in the same order of magnitude of the radius of gyration of the polymer.
Measurements provide insight into how and where the solvent is retained. GC results were supported by AFM results proving the method to be sensitive, precise and accurate.
[1] S. Bistac, J. Schutz Progress in Organic Coatings, 31 , 347-350 (1997)
[2] V. Shapovalov et al. Polym. Int., 49 , 432-436 (2000)