Slippage thin film/solid

Slippage at the Interface Between a Thin Film and a Solid. 118... 

Fig. 2 Velocity profile of liquid flow within a thin film (lubrication approximation). For the no-slip boundary condition (dashed line), the velocity at the substrate (z = 0) is zero. In the case of slippage (solid line), the liquid velocity is not zero at the substrate surface and only extrapolates to zero at a distance b (slippage length) within the substrate...

A material like polymer with large molecular weight, however, does not flow like an ideal liquid. The interfacial interactions between liquid molecules and the solid surface cause slippage of liquid on the smooth, passive solid surfaces [51-53]. Quite a lot of parameters like the nature of the liquid molecules [54,55], substrate roughness [56-59], nanoscale air bubbles in the liquid film [60,61], and the amount of water depletion on the surface [62] have infiuences on the slippage. A plug flow occurs in the thin film such that Equation (16.10) can then be simplified as... 

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