Influence of surface forces on hydrodynamics of wetting

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 1994-11, Vol.91, p.149-154
• Main Authors: Starov, Victor M., Kalinin, Vasiliy V., Ivanov, Vladimir I.
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; Long drop; Motion; Surface force; Surface physical chemistry
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/0927-7757(94)02876-1

It is well known that properties of thin liquid films deviate from those of a bulk liquid. Disjoining pressure was introduced by Derjaguin to describe thin liquid film behavior. The motion of a long oil drop or bubble under the action of an imposed pressure difference in a thin capillary filled with another immiscible liquid is investigated theoretically, taking into account the action of disjoining pressure. The velocity of the drop motion as a function of the pressure difference and the thickness of the film intervening between the drop and the capillary walls are calculated. The solution obtained coincides with Bretherton's equation at high velocities and deviates substantially at low velocities, which is a manifestation of disjoining pressure action in the thin film. In the same way, a problem concerning the thickness of a thin liquid film covering a thin solid thread drawing out from a liquid container is considered. The thickness of the film is calculated as a function of the thread velocity. The theoretical results obtained are in good agreement with known experimental data.