We investigate the dewetting of entangled and unentangled polymer films from model viscous polymer and inorganic substrates. Linear and hypergraft polyethyloxazoline (PEOX) polymers are chosen as the unentangled and entangled dewetting fluid, respectively. Holes nucleate at random positions in the film and slowly grow in the early stage of dewetting. This early stage of dewetting is found to be similar in the entangled and unentangled polymer films and to be largely independent of substrate. Late-stage dewetting in the entangled films is found to be significantly different because of the inhibition of hole coalescence in the intermediate stage of film dewetting. The holes in the entangled film continue to grow in size until they impinge on each other to form a foam-like structure with a uniform Acell@ size. The boundaries of these cells break-up and retract to the vertices to form a relatively uniform droplet configuration. In contrast, there is substantial hole coalescence in the unentangled polymer films in the intermediate stage of dewetting that leads to large and polydisperse hole patterns. Thus, entanglement has a large influence on the final morphology of dewetted polymer films.
Citation: Journal Of Polymer Science
Pub Type: Journals
dewetting, entanglement, hyperbranched polymers, polymer films