Dynamic contact angles

Angle to the main flow direction Surface coverage Advancing contact angle Dynamic contact angle Receding contact angle Density Eluid density Residual... 

Zhang J, Kwok DY (2006) Contact line and contact angle dynamics in supeifaydrophobic channels. Langmuir 22 4998-5004... 

The Wilhelmy slide has been operated in dynamic immersion studies to measure advancing and receding contact angles [59] (see Chapter X). It can also... 

In seeking to minimize the contact angle or to promote wetting of the adherend by the adhesive, one must consider the effects both of the chemistry of the components and of the morphology of the adherend surface on the observed contact angle. Finally, comment must be made on the dynamics of the wetting process and the factors upon which it depends. 

When spontaneous spreading occurs, the bulk of the advancing liquid is preceded by a precursor film, usually a few millimeters in width and a few hundred nanometers or less in thickness [58], as pictured in Fig. 12. The observed dynamic contact angle is that which is made by the bulk liquid against the precursor film, and it itself depends on the rate of the advance of the nominal interline. The relationship between the rate of spontaneous spreading, i.e. the rate of movement of the nominal interline normal to itself, (/, and the dynamic contact... 

Induction period measurements can also be used to determine interfacial tensions. To validate the values inferred, however, it is necessary to compare the results with an independent source. Hurley etal. (1995) achieved this for Cyanazine using a dynamic contact angle analyser (Calm DCA312). Solid-liquid interfacial tensions estimated from contact angle measurements were in the range 5-12 mJ/m which showed closest agreement with values (4—20mJ/m ) obtained from the log-log plots of induction time versus supersaturation based on the assumption of — tg. 

K. R. Shull, T. E. Karis. Dewetting dynamics for large equilibrium contact angles. Langmuir 70 334-339, 1994. 

Dynamic viscosity Kinematic viscosity Density Surface tension Shear stress Vapor quality Contact angle Shear viscosity Shear rate... 

As can be seen in Table 6.5, ONB in APG solution of concentration C = 100 ppm took place at significantly higher surface temperatures. It should be noted that the ONB in surfactant solutions may not be solely associated with static surface tension Sher and Hetsroni (2002). Other parameters such as heat flux, mass flux, kind of surfactant, surface materials, surface treatments, surface roughness, dynamic surface tension and contact angle need to be considered as well. 

Geld C (2004) Prediction of dynamic contact angle histories of a bubble growing at a wall. Int J Heat Fluid Flow 25 74—80... 

Assuming that the dynamic contact angle 9d is a sum of its basic value corresponding to stationary flow 0st and small perturbation 9 we arrive at the following relation for the fluctuation of capillary pressure... 

There is a number of theoretical and experimental relations determining the dependence of the dynamic contact angle on flow velocity (Dussan 1979 Ngan and Dussan 1982 Cox 1986 Blake 1994 Kistler 1993). Hoffman (1975) expressed the dynamic contact angle as a function solely of dimensionless parameters capillary number Ca... 

Blake TD (1993) Dynamic contact angles and wetting kinetics. In Berg JC (ed) Wettability. Dekker, New York, pp 251-309... 

Kom GA, Korn TM (1968) Mathematical handbook. McGraw-Hill, Boston Landau LD, Lifshitz EM (1959) Fluid mechanics, 2nd edn. Pergamon, London Morijama K, Inoue A (1992) The thermodynamic characteristics of two-phase flow in extremely narrow channels (the frictional pressure drop and heat transfer of boiling two-phase flow, analytical model). Heat Transfer Jpn Res 21 838-856 Ngan CD, Dussan EBV (1982) On the nature of the dynamic contact angle an experimental study. JEluidMech 118 27- 0... 

Practically, contact angles are measured as a function of time t after deposition of liquid drops. The spreading speed, U, is given by dridt, with r being the drop radius at time t. In the following, the dynamic contact angle will sometimes be expressed as a function of the spreading speed, U [0(0 = 0(0)]. 

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