Dewetting is the process by which thin films rupture to form holes that decay into ribbons and ultimately droplets. The topic of dewetting has received considerable attention due to desires to prevent it as well as control it for use as a tool to create patterned thin films. In this research, water soluble polymers - poly(vinyl alcohol) (PVOH), poly(allylamine hydrochloride) (PAH), poly(acrylic acid) (PAA), and poly(styrene sulfonate) (PSS) - were prepared on silicon wafers using either static adsorption or spin coating. The morphology and stability of a thin film to some extent depends on its thickness, which, via the Meyerhofer equation, can be related to the spin rate used to prepare the film during spin coating. However, this model for predicting film thickness does not distinguish between the portion of the film adsorbed spontaneously at the solution-substrate interface and the portion deposited during the spin and evaporation process. One of the goals of this study is to test a new model for predicting thin film thickness by decoupling the total film thickness into these two aforementioned components. The combination of static adsorption and spin coating methods allow for the isolation of the two thickness components of the thin films, while the wide range of hydrophilic polymers gives insight into the role of polymer crystallinity, hydrophobicity, and charge on the adsorption and deposition process, film wettability, and morphology. Current and future focuses of the project include manipulating polymer solution pH to allow for various combinations of polymer and substrate charge as well as distinguishing between stable and metastable films using thermal annealing.

Thickness, morphology and stability of hydrophilic polymers prepared on silicon wafers via spin coating

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.