Effect of Film Curvature on Drainage of Thin Liquid Films

Kumar, K. Vinoth; Nikolov, Alex; Wasan, Darsh T.

doi:10.1006/jcis.2001.8096

Cited by 37 publications

(28 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Manev et al [9] and Kumar et al [10] reported drainage times for aqueous foam films. Drainage times of emulsion films were measured by Traykov et al [11] and Manev et al [9].…”

Section: Resultsmentioning

confidence: 99%

“…Interference patterns of monochromatic light reflecting and transmitting through the thin film allow precise measurement of the film thickness. By surrounding the film with a gas or immiscible liquid, both foam [8][9][10] and emulsion films [9,11] can be studied. In this paper, the thinning velocities and drainage times of thin films predicted from various drainage models are compared to experimental measurements reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bounding film drainage in common thin films

Coons

Halley

McGlashan

et al. 2005

Colloids and Surfaces A: Physicochemical and Engineering Aspect

View full text Add to dashboard Cite

A review of thin film drainage models is presented in which the predictions of thinning velocities and drainage times are compared to reported values on foam and emulsion films found in the literature. Free standing films with tangentially immobile interfaces and suppressed electrostatic repulsion are considered, such as those studied in capillary cells.The experimental thinning velocities and drainage times of foams and emulsions are shown to be bounded by predictions from the Reynolds and the theoretical MTsR equations. The semi-empirical MTsR and the surface wave equations were the most consistently accurate with all of the films considered. These results are used in an accompanying paper to develop scaling laws that bound the critical film thickness of foam and emulsion films.

show abstract

“…Manev et al [9] and Kumar et al [10] reported drainage times for aqueous foam films. Drainage times of emulsion films were measured by Traykov et al [11] and Manev et al [9].…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bounding film drainage in common thin films

Coons

Halley

McGlashan

et al. 2005

Colloids and Surfaces A: Physicochemical and Engineering Aspect

View full text Add to dashboard Cite

show abstract

“…Figure 3. Critical thickness measurements reported for numerous foam (Exerowa and Kolarov, 1966;Vrij, 1966a;Scheludko and Manev, 1968;Rao et al, 1982;Radoev et al, 1983;Manev et al, 1984;Kumar et al, 2002) and emulsion (Traykov et al, 1977;Manev et al, 1984) films compared to scaling law predictions for the upper (square) and lower (triangle) critical film thickness. Thickness measurements on foam films are indicated by open symbols and those on emulsion films by closed symbols.…”

Section: The Bounding Equationsmentioning

confidence: 99%

“…Despite decades of experimental (Ivanov et al, 1970;Traykov et al, 1977;Rao et al, 1982;Radoev et al, 1983;Manev et al, 1984;Kumar et al, 2002) and theoretical (Vrij, 1966a;Sheludko, 1967;Ivanov et al, 1970;Radoev et al, 1983;Sharma and Ruckenstein, 1987) investigation into the stability and rupture of thin films, very little has been published on their scaling behaviour. Thin liquid films form between the dispersed phase in emulsions and foams and become unstable when long range van der Waals forces induce the growth of capillary waves on the film interfaces (Vrij, 1966a).…”

Section: Introductionmentioning

confidence: 99%

“…The onset of instability occurs at the maximum transition thickness, which is the transition thickness of the waveform that is first to develop a positive growth rate. The instability arises when long range van der Waals (attractive) forces acting between the interfaces overcome the interfacial capillary forces (Manev et al, 1984;Kumar et al, 2002) and emulsion films (Traykov et al, 1977;Manev et al, 1984) as compared to the drainage times predicted from the Reynolds equation (triangles) and MTsR theory (squares). Drainage times of foam films are indicated by open symbols and those of emulsion films by closed symbols.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bounding the Stability and Rupture Condition of Emulsion and Foam Films

Coons

Halley

McGlashan

et al. 2005

Chemical Engineering Research and Design

View full text Add to dashboard Cite

A scaling law is presented that provides a complete solution to the equations bounding the stability and rupture of thin films. The scaling law depends on the fundamental physicochemical properties of the film and interface to calculate bounds for the critical thickness and other key film thicknesses, the relevant waveforms associated with instability and rupture, and film lifetimes. Critical thicknesses calculated from the scaling law are shown to bound the values reported in the literature for numerous emulsion and foam films. The majority of critical thickness values are between 15 to 40% lower than the upper bound critical thickness provided by the scaling law.Keywords: thin films; stability; critical thickness; spontaneous rupture; scaling law. INTRODUCTIONDespite decades of experimental (Ivanov et al., 1970;Traykov et al., 1977;Rao et al., 1982;Radoev et al., 1983;Manev et al., 1984;Kumar et al., 2002) and theoretical (Vrij, 1966a;Sheludko, 1967;Ivanov et al., 1970;Radoev et al., 1983;Sharma and Ruckenstein, 1987) investigation into the stability and rupture of thin films, very little has been published on their scaling behaviour. Thin liquid films form between the dispersed phase in emulsions and foams and become unstable when long range van der Waals forces induce the growth of capillary waves on the film interfaces (Vrij, 1966a). Upon reaching a critical thickness, films either rupture or shift to a uniform thickness and form a black film (Manev et al., 1974). Vrij (1966a, b) derived limiting equations for the critical thickness under conditions where either the Plateau border pressure drop or disjoining pressure control film drainage. Many films drain under conditions that fit into the intermediate region where both pressure terms are significant and the limiting equations are not applicable. Vrij's unique theoretical approach forced the critical thickness predictions to lower values by applying a wave-averaged corrugation growth rate expression and by specifying the rupture thickness from the film drainage curve at the minimum lifetime. The lower critical thickness predictions were still much larger than the experimental values on aniline and aqueous foam films. In this case, the overprediction was exacerbated by application of Reynolds equation and unusually large Hamacker constants. Vrij used 7 Â 10 219 J for aniline and 10 219 J for aqueous films, when the non-retarded Hamacker constant predicted from Lifshitz theory is 6.5 Â 10 220 J and 3.6 Â 10 220 J, respectively (Coons et al., 2005b). Vrij also included an undefined parameter ( f), which was inexplicably set to 6.5 and 7 for the validation films. While application of Vrij's limiting equations has the advantage of being relatively simple, frequent discrepancy with experimental results reduce their overall appeal. Ivanov et al. (1970) applied the same corrugation growth rate expressions as Vrij, but based the critical condition upon the first waveform to reach the centre of the film. This rupture criterion increases the critical film thickness...

show abstract

Non‐Ionic Micelle Films: Thinning and Stability

Nikolov

Wasan

2007

Colloid Stability and Application in Pharmacy

View full text Add to dashboard Cite

Effect of Film Curvature on Drainage of Thin Liquid Films

Cited by 37 publications

References 13 publications

Bounding film drainage in common thin films

Bounding film drainage in common thin films

Bounding the Stability and Rupture Condition of Emulsion and Foam Films

Non‐Ionic Micelle Films: Thinning and Stability

Contact Info

Product

Resources

About