Chemical and Biomolecular Engineering Research and Publications


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© 2003 American Chemical Society. The American Chemical Society allows the posting of only the title, abstract, tables, and figures from articles appearing in the Macromolecules. This article was published on web 03/13/2003 Macromolecules, Vol. 36, No. 7, 2003 10.1021/ma0212792 CCC © 2003 American Chemical Society. This article can be viewed at the publishers site:


ABSTRACT: One way to produce high order in a block copolymer thin film is by solution casting a thin film and slowly evaporating the solvent in a sealed vessel. Such a solvent-annealing process is a versatile method to produce a highly ordered thin film of a block copolymer. However, the ordered structure of the film degrades over time when stored under ambient conditions. Remarkably, this aging process occurs in mesoscale thin films of polystyrene-polyisoprene triblock copolymer where the monolayer of vitrified 15 nm diameter polystyrene cylinders sink in a 20 nm thick film at 22 °C. The transformation is studied by atomic force microscopy (AFM). We describe the phenomena, characterize the aging process, and propose a semiquantitative model to explain the observations. The residual solvent effects are important but not the primary driving force for the aging process. The study may lead to effective avenue to improve order and make the morphology robust and possibly the solvent-annealing process more effective.

coplymer thinn film.doc (1915 kB)
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