Viscosity of surfactant stabilized emulsions

Jansen, K.M.B.; Agterof, W.G.M.; Mellema, J.

doi:10.1122/1.1410372

Cited by 24 publications

(20 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To capture the apparent viscosity of the fluid surrounding the drops, the continuous phase viscosity should be replaced with the emulsion viscosity for non-dilute oil mixtures. To generate a predictive model, the emulsion viscosity η em must be calculated from known variables including the shear rate γ, the oil volume fraction ϕ, density ρ d and viscosity η d , the continuous phase density ρ c and viscosity η c , the surfactant concentration and the temperature T. Several models have been developed predicting the emulsion viscosity from these variables (Derkach, 2009;Pal, 2001;Jansen et al, 2001;Barnes, 1994). At very low shear rates, the oil drops exist in a three-dimensional isotropic and random distribution resulting in a constant viscosity.…”

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

“…At very high shear rate, drops cannot align any further and the emulsion behaves as a Newtonian fluid with a constant viscosity. Assuming no temperature change during emulsification, the emulsion viscosity was predicted as a function of the shear rate using the following model (Jansen et al, 2001):…”

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

“…where d 32 is the Sauter mean diameter of the emulsion drops; d m is hydrodynamic diameter of the surfactant molecule (assumed to be 30 A o based on typical values of d m ); ϕ c is the critical oil volume fraction above which drops are in close contact and the interaction mechanism changes (assumed to be 0.6 from Jansen et al, 2001); k is the Boltzmann constant ð1:38 Â 10 À 23 J=KÞ; K λ , K, m, and a 1 are fitting parameters for ϕrϕ c ; and a 2 and a 3 are additional fitting parameters for ϕ4ϕ c . As the shear rate _ γ in increased, the ratio η em =η c asymptotically approaches the value η 1 .…”

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

See 2 more Smart Citations

Prediction of emulsion drop size distributions in colloid mills

Maindarkar

Dubbelboer

Meuldijk

et al. 2014

Chemical Engineering Science

View full text Add to dashboard Cite

Developed a population balance equation model for emulsification in colloid mill. Derived the function for drop breakage frequency in simple shear flow. Proposed a new daughter drop distribution function for capillary drop breakage. Used a viscosity model to predict the emulsion viscosity at high shear rates. Demonstrated good agreement between measured and predicted drop size distributions. Colloid mills are the most common emulsification devices used in industry for products with high oil content. Drop breakage occurs when the emulsion is flowed through a small gap between rotor and stator under laminar shear conditions. In this paper, we have developed the first full population balance equation (PBE) model for colloid mills and used the model to better understand the relevant drop breakage mechanisms. The PBE model accounted for both drop breakage and coalescence and generated predictions of the drop size distribution after each pass of the emulsion through the colloid mill. Drops were assumed to break due to capillary instability with the distribution of drop sizes resulting from each breakage event studied in detail. A viscosity model was developed to predict the emulsion viscosity as function of the oil fraction and the high shear rates commonly used. Nonlinear optimization was used to estimate adjustable parameters in the breakage and coalescence functions to minimize the least-squares difference between predicted and measured drop size distributions for high oil-to-surfactant emulsions. We concluded that experimentally observed drop volume distributions could not be predicted with daughter drop distribution functions reported in the literature. Improved predictions were obtained using a new bimodal distribution function which captured drop breakage into multiple, nearly uniform daughter drops with a large number of small satellite drops. We also investigated model extensibility for changes in the oil fraction, emulsion flow rate and rotor speed.Published by Elsevier Ltd.

show abstract

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

Section: Emulsion Viscosity Modelmentioning

confidence: 99%

See 1 more Smart Citation

Prediction of emulsion drop size distributions in colloid mills

Maindarkar

Dubbelboer

Meuldijk

et al. 2014

Chemical Engineering Science

View full text Add to dashboard Cite

show abstract

“…31 The emulsion viscosity η em was calculated using an empirical equation 32 that accounts for the effects of ϕ, η d , and η c . 21,29 Surfactant Adsorption Model…”

Section: ■ Appendix Population Balance Equationmentioning

confidence: 99%

Achieving Target Emulsion Drop Size Distributions Using Population Balance Equation Models of High-Pressure Homogenization

Maindarkar

Hoogland

Henson

2015

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Population balance equation (PBE) models have been used extensively to predict drop size distributions (DSDs) of dispersed phase systems. In our previous publications, we have used the PBE framework to develop increasingly sophisticated process models for oil-in-water emulsification in high-pressure homogenizers. The goal of this study was to utilize these PBE models for integrated emulsion product and process design through the formulation and solution of homogenizer optimization problems. For a specified number of homogenization passes, the initial amount of surfactant and the pressure of each pass were determined by solving a nonlinear least-squares optimization problem such that the target DSD were achieved. Three alternative objective functions that differed with respect to the distribution specification and the penalty on surfactant usage were formulated and solved for different target DSDs. The model predictions were successfully validated by performing homogenization experiments using the optimized formulation and homogenization variables.

show abstract

“…Increasing the drive voltage to its maximum (40 V) did not resolve this problem, and increasing the printhead temperature aggravated it by boiling off the solvent prematurely and causing curing of the ink in the nozzle and on the nozzle plate. Moreover, ink viscosity can be affected by the addition of surfactant [21] and by changes in the ambient temperature. Therefore, considering these factors, a target viscosity in the range of 5-6 cP was chosen.…”

Section: Ink Formulationmentioning

confidence: 99%

Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) Inkjet Inks Doped with Carbon Nanotubes and a Polar Solvent: The Effect of Formulation and Adhesion on Conductivity

Angelo

2010

Journal of Adhesion Science and Technology

View full text Add to dashboard Cite

A conductive aqueous polymer suspension of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), or PEDOT:PSS, was used as the basis for an inkjet-printable and translucent conductive material. Several types of surfactants were used to achieve suitable particle sizes for inkjet printing, with Zonyl™ FS-300 non-ionic surfactant providing suitable surface tension, stability and dispersion. Viscosity was controlled using water and glycerol. Glycerol was also included as a humectant. 10 w/w% polar solvent (dimethyl sulfoxide) was used to increase conductivity, as a co-solvent and as a viscosity modifier. Carbon nanotubes, both single-and multi-walled, were dispersed in the ink to further improve its conductivity. The optimized ink was printed onto coated photo-paper and cellulose acetate (CA) substrates and characterized for ink layer thickness and conductivity. The effect of paper folding and peeling of an adhesive strip from the ink surface on the conductivity of the printed samples was also characterized. Optical microscopy showed that the conductive ink was contained almost entirely in the pores of the photo-paper coating layer and fibres, but remained as a film on the CA surface. In the case of photo-paper, failure occurred primarily at the coating-paper interface. The cohesive failure compromised the conductivity of the PEDOT:PSS layer contained in the coating. In the case of CA (within the coating layer), the PEDOT:PSS film's conductivity was not significantly affected by folding or peeling. This suggests that PEDOT:PSS is a robust conductive material well-suited to applications requiring significant flexibility.

show abstract

Viscosity of surfactant stabilized emulsions

Cited by 24 publications

References 34 publications

Prediction of emulsion drop size distributions in colloid mills

Prediction of emulsion drop size distributions in colloid mills

Achieving Target Emulsion Drop Size Distributions Using Population Balance Equation Models of High-Pressure Homogenization

Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) Inkjet Inks Doped with Carbon Nanotubes and a Polar Solvent: The Effect of Formulation and Adhesion on Conductivity

Contact Info

Product

Resources

About