Dynamic contact lines

Sheng P, Zhou M (1992) Immiscible-fluid displacement contact-line dynamics and the velocity-dependcmt capillary pressure. Phys Rev A 45 5694-5708... 

Zhang J, Kwok DY (2004) Lattice Boltzmann study on the contact angle and contact line dynamics of liquid-vapor interfaces. Langmuir 20 8137-8141... 

With I = 5, i = 2 already set [50, 52, 53] experiments are well rendered by equation (6) with a single parameter go 7, well within the expected range.] It is, moreover, interesting to note that the theoretical description involving the contact line dynamics does predict a yiv/hL dependence of U, for a fixed wettability 9o). Such behavior, already mentioned, is experimentally well verified as shown in Fig. 5. 

Dussan EBV (1979) On the spreading of liquids on solid surfaces static and dynamic contact lines. Ann Rev Fluid Mech 11 371 00... 

While the above refers mainly to the static limit, new effects come into play when a moving contact line, i.e. spreading, is considered. It has been observed experimentally that the contact angle of a moving contact line 0, the dynamic contact angle, deviates from the corresponding static value 0. As an example, for a completely wettable surface (i.e. 6(, = 0), a relationship of the form... 

ADSA-P has been employed in various surface tension and contact angle studies, including static (advancing) contact angles [69.70], dynamic (advancing) contact angles at slow motion of the three-phase contact line [4, 71—74], and contact angle kinetics of surfactant solutions [75]. A schematic of the experimental setup for ADSA-P sessile drops is shown in Fig. 6. More details are available elsewhere [66[. 

Figure 5.36. Molecular dynamics pictures of liquid motion near the contact line. Partial wetting. Given is the height as a function of horizontal position, both In reduced units. Panel (a) initial stage of spontaneous wetting, (c) intermediate stage, (d) fined stage. Panel (b) corresponds to panel (a), but is taken with respect to the position of the contact line. The solid is at h = 0.55. (Courtesy of M. de Ruijter and J. De Coninck.)...

Dynamic Sorption of Ink Jet Ink Drops on Commercial Papers. Drying times (t ) and various parameters measured or derived from contact line spreading, profile development and penetration data for the various systems studied are summarized in Table I. A wide variation occured in the values of tj among the various papers studied. The maximum deviations in tdetailed contact line and profile analysis suggest that these deviations result from the structural variability in paper rather than drop-to-drop volume variations. This was substantiated by the marked variations in the final image shape observed among several drops printed on the same paper sample. 

It is important to remember that many dynamic wetting processes act in the presence of wetting agents as a special type of surfactants. In contrast to very low displacements of the contact line where no shear stresses exist and the adsorption equilibrium is established, at higher speeds the modelling of the process (overlap of surface energetic and hydrodynamic forces) becomes very difficult and a lot of boundary conditions must be simplified. 

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