Dry-spot nucleation in thin liquid films on chemically patterned surfaces

Abstract

We systematically study the influence of chemical patterning on the instability of thin liquid films induced by chemical heterogeneities on a flat, horizontal, and partially wetting substrate. We consider common geometric shapes like wedges, circles, and stripes and determine the time required for nucleation of a dry-spot as a function of film thickness, contact angle, pattern dimensions, and geometry. Moreover, we characterized the resulting liquid distribution and identified conditions that avoid the formation of residual droplets on the less wettable regions, which is usually undesirable in technological applications.

Thin-film models of liquid displacement on chemically patterned surfaces for lithographic printing processes

“…While a number of simplifications necessarily had to be made, the model we develop provides a relatively simple way to obtain estimates for important process parameters, and can serve as the basis for the development of more sophisticated models. In particular, it will be important to account for the mechanics of liquid transfer from one surface to another (e.g., from printing plate to blanket roll) as the surfaces separate, residual ink on the image areas [27], the influence of liquid additives on surface wettability [42], three-dimensional effects [43], and more realistic forms of the disjoining pressure [44].…”

Fabrication of flexible microlens arrays through vapor-induced dewetting on selectively plasma-treated surfaces

“…3(a), the initially smooth thin film broke up and a circular dry hole was formed, which can be attributed to the rupture mechanism of ''heterogeneous nucleation'' due to a microscale wettability contrast. 17,41,42 Such instability was manifested after 30 s exposure to the solvent vapor. After the nucleation, the dry hole grew laterally with time to form a dewetted region with a three-phase contact line progressively expanding ahead of the hole (Fig.…”

Patterns formed in a thin film with spatially homogeneous and non-homogeneous Derjaguin disjoining pressure

“…Chemically patterned substrates are an efficient way to obtain microstructures of different shapes by using different types of substrate patterning [34]. Chemical modification of substrates can also be used to avoid spontaneous breakup of thin films, which is often highly undesirable, as, for example, in printing technology [1,5].…”