Adsorption process at the surface of laminar flowing liquid films

Adsorption Process at the Surface of Laminar Flowing Liquid Films 

In coating processes the problem of controlling the flow of liquids down an inclined plate is a key question (Scriven 1960, Kretzschmar 1974). Therefore, the hydrodynamic flow of such films in combination with surface rheological and adsorption kinetics models were described. As the principle of a flowing film can be used also as a separate method to study adsorption processes in the range of milliseconds, the theory is presented here, while the experimental details are given in the next chapter. 

The situation of a liquid film flowing down a plate is represented in Fig. 4.15. 

The flow velocities u and v are directed along and normal to the flow direction, x, y and z are the corresponding spatial coordinates, a is the angle of inclination, and h is the thickness of the liquid film. The hydrodynamic problem may be simplified by neglecting the entrance region at x=0 (Van den Bogaert Joos 1979), 

The integration of the flow problem yields (van den Bogaert Joos 1979) pg sina 2 / 1 dy pgh.  

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