Spin coating is one of the most common methods for thin film fabrication. Here, it is evaluated as a tool both for studying dopamine (DA) oxidative polymerization in solution, and preparing polydopamine thin films on native and functionalized silicon wafers. Sodium periodate was chosen as the oxidant because it is strong and exhibits fast reaction kinetics. All the DA solutions were prepared in acidic acetate buffers to avoid interference from oxidation by oxygen. The main feature investigated was DA reaction time prior to coating. This uniquely permitted taking snapshots of PDA particle size and surface adhesiveness as a function of reaction time. Other variables studied were surface chemistry, solution pH, DA concentration, and solution contact time prior to spin. Results indicated that controlling reaction kinetics, mostly in terms of solution pH and DA concentration, is most critical in order to produce thick and homogeneous PDA films. Surface chemistry also has a significant effect on film growth kinetics and morphology as well as PDA film stability in aqueous and organic media.

Using spin coating to fabricate polydopamine thin films

2019 Fall National Meeting

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