Characterisation, modification and mathematical modelling of sudsing

L. Ran, S.A. Jones, B. Embley, M.M. Tong, P.R. Garrett, S.J. Cox, P. Grassia, S.J. Neethling

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A programme of research is outlined which considers the foaming performance and foam behaviour of surfactant systems commonly encountered in hand-wash laundry detergent applications. An experimental study of the physical chemistry of foam generation indicates that precipitation of a typical anionic surfactant with calcium forms mesophase particles and causes a marked reduction in the rate of transport of surfactant to air–water surfaces and a concomitant reduction in foaming. Oily soil antifoam effects are however insensitive to the presence of calcium, being equally effective regardless of pH and calcium content. They may be reproduced by a simple particle–oil mixture of a saturated and an unsaturated triglyceride (e.g. tristearin and triolein respectively). A detailed foam rheometry study is performed using foam flowing through a constriction. Bubble shapes are used to deduce the normal and shear stresses across the foam flow field. Broad agreement between the experimental stress field and that obtained from quasistatic simulations is demonstrated. As foam flow-rate increases, a different model, which takes explicit account of viscous dissipative forces within the foam flow field is required. The dissipative foam flow model predicts differential shrinkage and stretch rates of foam films. Coupled to a model for surfactant transport, this shows the extent to which surfactant concentration accumulates in shrinking films and is depleted in stretching films. In addition to film stretching, it is also important to know about film bursting or failure rates. Here failure rates are estimated using capillary suction pressures exerted on the films by Plateau border channels around film edges. The failure rates can then be employed to predict the evolution of bubble size at various spatial locations in a foam: reasonable agreement with experimental bubble size distributions is obtained.
LanguageEnglish
Pages50-57
Number of pages8
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume382
Issue number1-3
Early online date24 Nov 2010
DOIs
Publication statusPublished - 5 Jun 2011

Fingerprint

foams
Foams
Surface-Active Agents
surfactants
Surface active agents
calcium
Calcium
foaming
bubbles
Stretching
Flow fields
flow distribution
Triolein
Laundries
Physical chemistry
detergents
Anionic surfactants
physical chemistry
Capillarity
Detergents

Keywords

  • foams
  • surfactant chemistry
  • fatty soils
  • foamability
  • rheometry
  • dissipative effects
  • continuum modelling

Cite this

Ran, L., Jones, S. A., Embley, B., Tong, M. M., Garrett, P. R., Cox, S. J., ... Neethling, S. J. (2011). Characterisation, modification and mathematical modelling of sudsing. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 382(1-3), 50-57. https://doi.org/10.1016/j.colsurfa.2010.11.028
Ran, L. ; Jones, S.A. ; Embley, B. ; Tong, M.M. ; Garrett, P.R. ; Cox, S.J. ; Grassia, P. ; Neethling, S.J. / Characterisation, modification and mathematical modelling of sudsing. In: Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2011 ; Vol. 382, No. 1-3. pp. 50-57.
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Characterisation, modification and mathematical modelling of sudsing. / Ran, L.; Jones, S.A.; Embley, B.; Tong, M.M.; Garrett, P.R.; Cox, S.J.; Grassia, P.; Neethling, S.J.

In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 382, No. 1-3, 05.06.2011, p. 50-57.

Research output: Contribution to journalArticle

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T1 - Characterisation, modification and mathematical modelling of sudsing

AU - Ran, L.

AU - Jones, S.A.

AU - Embley, B.

AU - Tong, M.M.

AU - Garrett, P.R.

AU - Cox, S.J.

AU - Grassia, P.

AU - Neethling, S.J.

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N2 - A programme of research is outlined which considers the foaming performance and foam behaviour of surfactant systems commonly encountered in hand-wash laundry detergent applications. An experimental study of the physical chemistry of foam generation indicates that precipitation of a typical anionic surfactant with calcium forms mesophase particles and causes a marked reduction in the rate of transport of surfactant to air–water surfaces and a concomitant reduction in foaming. Oily soil antifoam effects are however insensitive to the presence of calcium, being equally effective regardless of pH and calcium content. They may be reproduced by a simple particle–oil mixture of a saturated and an unsaturated triglyceride (e.g. tristearin and triolein respectively). A detailed foam rheometry study is performed using foam flowing through a constriction. Bubble shapes are used to deduce the normal and shear stresses across the foam flow field. Broad agreement between the experimental stress field and that obtained from quasistatic simulations is demonstrated. As foam flow-rate increases, a different model, which takes explicit account of viscous dissipative forces within the foam flow field is required. The dissipative foam flow model predicts differential shrinkage and stretch rates of foam films. Coupled to a model for surfactant transport, this shows the extent to which surfactant concentration accumulates in shrinking films and is depleted in stretching films. In addition to film stretching, it is also important to know about film bursting or failure rates. Here failure rates are estimated using capillary suction pressures exerted on the films by Plateau border channels around film edges. The failure rates can then be employed to predict the evolution of bubble size at various spatial locations in a foam: reasonable agreement with experimental bubble size distributions is obtained.

AB - A programme of research is outlined which considers the foaming performance and foam behaviour of surfactant systems commonly encountered in hand-wash laundry detergent applications. An experimental study of the physical chemistry of foam generation indicates that precipitation of a typical anionic surfactant with calcium forms mesophase particles and causes a marked reduction in the rate of transport of surfactant to air–water surfaces and a concomitant reduction in foaming. Oily soil antifoam effects are however insensitive to the presence of calcium, being equally effective regardless of pH and calcium content. They may be reproduced by a simple particle–oil mixture of a saturated and an unsaturated triglyceride (e.g. tristearin and triolein respectively). A detailed foam rheometry study is performed using foam flowing through a constriction. Bubble shapes are used to deduce the normal and shear stresses across the foam flow field. Broad agreement between the experimental stress field and that obtained from quasistatic simulations is demonstrated. As foam flow-rate increases, a different model, which takes explicit account of viscous dissipative forces within the foam flow field is required. The dissipative foam flow model predicts differential shrinkage and stretch rates of foam films. Coupled to a model for surfactant transport, this shows the extent to which surfactant concentration accumulates in shrinking films and is depleted in stretching films. In addition to film stretching, it is also important to know about film bursting or failure rates. Here failure rates are estimated using capillary suction pressures exerted on the films by Plateau border channels around film edges. The failure rates can then be employed to predict the evolution of bubble size at various spatial locations in a foam: reasonable agreement with experimental bubble size distributions is obtained.

KW - foams

KW - surfactant chemistry

KW - fatty soils

KW - foamability

KW - rheometry

KW - dissipative effects

KW - continuum modelling

U2 - 10.1016/j.colsurfa.2010.11.028

DO - 10.1016/j.colsurfa.2010.11.028

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SP - 50

EP - 57

JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects

T2 - Colloids and Surfaces A: Physicochemical and Engineering Aspects

JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects

SN - 0927-7757

IS - 1-3

ER -