Nucleation Radius and Growth of a Liquid Meniscus

✍ Scribed by Georges Debregeas; Françoise Brochard-Wyart

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 479 KB
• Volume: 190
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1997.4855

✦ Synopsis

We consider a horizontal solid plate P placed above the free e õ e c Å 02S rg Å 2k 01 cos u 2 , [1] surface of a liquid L separated by a layer of air of thickness e ( Ç0.1 mm) . With suitable P / L pairs this layer of air is metastable

where k 01 is the capillary length ( k 2 Å rg /g l/o ) and u is

for thicknesses e below a certain limit ec ( Ç1 mm). We have found a way of setting up bridges connecting the liquid surface with the the equilibrium contact angle.

plate in a controlled way ( axisymmetric meniscus of horizontal

We will be concerned in the following with air layers radius R) . The meniscus grows if R is above a certain threshold of thickness e õ ec . One useful approach to display the R c (e ) . If R õ R c the meniscus shrinks to zero. Our method allows metastability amounts to ''drilling a hole'' in the air film, precise measurements of R c (e ): We were able to do this using i.e., to bridge (L ) and ( P ) by an axisymmetric meniscus silicone oils and two types of plates P ( with different contact with a certain radius R. Experimentally we achieve this by angles ) . Our results are in good agreement with classical calculastarting with a liquid contained in a Petri dish. If we raise tions by G. I. Taylor and E. Michael ( J. Fluid Mech. 58, 625 the dish we can establish contact between ( L ) and ( P ) using ( 1973 ) ). Furthermore, When R ú R c (e ) , we find that R grows a pendant droplet attached to the solid surface. If we then linearly with time t and that move the dish downward by a distance e, we have achieved the bridge under discussion. dR dt ϰ e 00.7 ͩ 1 0 ͩ e ec ͪ 2 ͪ .

This experiment can be related to the study of the stability of a liquid film of thickness e deposited on a substrate when a hole of radius R is made. The part played by the liquid