Regensburg 2007 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: POSTER: Colloids and Nanoparticles
CPP 9.3: Poster
Monday, March 26, 2007, 16:00–18:00, Poster B
Front instabilities in evaporating films of nanoparticle suspensions - simulation results — •Ioan Vancea1, Christopher Martin2, Emmanuelle Vaujour2, Philip Moriarty2, and Uwe Thiele1 — 1Max-Planck-Institut fur Physik komplexer Systeme, Noethnitzer Str. 38, D-01187 Dresden, Germany — 2School of Physics & Astronomy, The University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
Various experimental settings involving drying suspensions of nanoparticles have been used to produce patterned nanoparticle layers [1,2]. Beside polygonal networks and spinodal structures one finds branched structures.
Using a variant of a Monte Carlo model introduced by Rabani et al. [1], we study front instabilities of initially straight or circular fronts.
We discuss in detail the influences that lead to the fingered structures. We show that even with a simple model including evaporation as the only dynamic process it is possible to determine many properties of the finger patterns.
Especially, we present results for a straight dewetting front that becomes transversally unstable depending on driving force (chemical potential), nanoparticle concentration and mobility (inverse of an effective viscosity). The fingering becomes stronger with increasing chemical potential and decreasing mobility. Concepts of quantification of the fingering are also discussed.
[1] E. Rabani et al., Nature 426, 271-274 (2003).
[2] C. P. Martin et al., Nano Lett. 4, 2389-2392 (2004).