Thin liquid films on chemically heterogeneous substrates: self-organization, dynamics and patterns in systems displaying a secondary minimum

Ashutosh Sharma, Rahul Konnur and Kajari Kargupta

Physica A: Statistical Mechanics and its Applications, 2003, vol. 318, issue 1, 262-278

Abstract: Surface instability in a thin liquid film engendered by a micro-scale wettability contrast, resulting from the spatial gradients in the intermolecular interactions, is investigated based on 3D simulations for a system displaying both the primary and secondary minima in its force vs. distance curve. Characteristic dynamical and morphological features of the evolution on a chemically heterogeneous substrate are identified for two different cases: (a) a single patch or step of heterogeneity (b) multiple periodically arranged stripes of heterogeneity. The presence of heterogeneity can cause true rupture at the primary minimum by surmounting the energy barrier between the two minima. The breakup time on heterogeneous surfaces varies inversely with the gradient in the potential induced by the heterogeneity and can be several orders of magnitude smaller than the spinodal dewetting time on homogeneous surfaces. Heterogeneity can also cause rupture in spinodally stable films and produce complex and locally ordered morphological features (e.g., ripples) absent in the spinodal dewetting. On a chemically patterned surface composed of alternating more and less wettable stripes, film breakup is suppressed on some potentially destabilizing nonwettable sites when their spacing is below a characteristic lengthscale of instability, λh which is close to the spinodal lengthscale. Thin film pattern ideally replicates the surface energy pattern only when, (a) the periodicity of substrate pattern is greater than λh, (b) width of the less wettable stripe is lower than a transition length above which complex morphological features are formed.

Keywords: Thin films; True dewetting; Pseudo dewetting; Chemical heterogeneity; Pattern formation; Templating (search for similar items in EconPapers)
Date: 2003
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378437102014292
Full text for ScienceDirect subscribers only. Journal offers the option of making the article available online on Science direct for a fee of $3,000

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:phsmap:v:318:y:2003:i:1:p:262-278

DOI: 10.1016/S0378-4371(02)01429-2

Access Statistics for this article

Physica A: Statistical Mechanics and its Applications is currently edited by K. A. Dawson, J. O. Indekeu, H.E. Stanley and C. Tsallis

More articles in Physica A: Statistical Mechanics and its Applications from Elsevier
Bibliographic data for series maintained by Catherine Liu ().