COLL 191 |
| Thin films (5-20 nm) of poly(2vinyl pyridine) (PVP) deposited on silicon oxide surface have been found to form dewetting pattern when treated with basic solutions (pH >= 10). The dependence of pattern morphology on molecular weight and thickness of the polymer layer has been studied. Formation of two distinctive structures has been observed. The structure formed by large drops of polymer is characteristic for the polymer of low molecular weight (11 kDa) and smallest thickness of the polymer layer, whereas other samples form web-like pattern upon dewetting. The polymer showed partially reversible behavior towards flat film when exposed to pH 4 buffer solution. More complex structures can be obtained by consecutive treatments with acidic (pH 4) and basic (pH 10) solutions. Atomic force microscopy (AFM) was used to study both, morphology and elastic properties, of the polymer in media of different acidity in order to determine the mechanism behind the dewetting process. |
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Fundamental Research in Colloid and Surface Chemistry
6:00 PM-8:00 PM, Monday, August 20, 2007 BCEC -- East Registration, Poster
Division of Colloid & Surface Chemistry |