Slip effects in polymer thin films

Department of Experimental Physics, Saarland University, D-66041 Saarbrücken, Germany.
Journal of Physics Condensed Matter (Impact Factor: 2.35). 01/2010; 22(3):033102. DOI: 10.1088/0953-8984/22/3/033102
Source: PubMed


Probing the fluid dynamics of thin films is an excellent tool for studying the solid/liquid boundary condition. There is no need for external stimulation or pumping of the liquid, due to the fact that the dewetting process, an internal mechanism, acts as a driving force for liquid flow. Viscous dissipation, within the liquid, and slippage balance interfacial forces. Thus, friction at the solid/liquid interface plays a key role towards the flow dynamics of the liquid. Probing the temporal and spatial evolution of growing holes or retracting straight fronts gives, in combination with theoretical models, information on the liquid flow field and, especially, the boundary condition at the interface. We review the basic models and experimental results obtained during the last several years with exclusive regard to polymers as ideal model liquids for fluid flow. Moreover, concepts that aim to explain slippage on the molecular scale are summarized and discussed.

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    • "In order to test the self-similarity of the form of the rim, the rim width w (the distance between three-phase contact line and the point, where the rim height has dropped to 110% of the initial film thickness) is plotted as function of the maximum rim height H, c.f. Fig. 9b. The linear dependence indicates that self-similarity can safely be assumed and w ∝ √ R (where R denotes the radius of the hole) is obtained from the conservation of volume for growing holes (see Ref. [44]). "
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    • "Up to date many factors have been found that seem to influence the boundary conditions [20] [21] [22]. The least controversially discussed amongst them is the fluid-wall interaction [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34]. Shear rates beyond a critical value are supposed to induce slip, too [35] [36] [37] [38]. "
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