Production of O/W emulsions using SPG membranes, ceramic α-aluminium oxide membranes, microfluidizer and a silicon microchannel plate—a comparative study

Vladisavljević, Goran T.; Lambrich, Uwe; Nakajima, Mitsutoshi; Schubert, Helmar

doi:10.1016/j.colsurfa.2003.10.026

Cited by 113 publications

(69 citation statements)

References 20 publications

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“…The effect of rotational speed on the mean droplet size found here is similar to the effect of cross flow velocity in cross flow membrane emulsification [10]. However, it is especially important to note that the droplet/pore size ratio for the given stainless steel membrane is much smaller than for the Shirasu porous glass (SPG) and ceramic membranes investigated by Vladisavljević et al [10].…”

Section: Resultssupporting

confidence: 81%

“…Several single-drop technologies have been developed for generating uniform droplets, such as injection of liquid through a capillary into another co-flowing immiscible fluid [3,4], penetration of dispersed phase through microfabricated parallel silicon channels [5] or interconnected channel network in microfluidic devices [6,7], and injection of dispersed phase through microporous membranes of different nature (glass, ceramic, metallic, polymeric) [8][9][10][11][12][13][14]. Production of various particulate products, such as microspheres and microcapsules, using membrane emulsification routes was recently reviewed by Vladisavljević and Williams [15].…”

Section: Introductionmentioning

confidence: 99%

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Manufacture of large uniform droplets using rotating membrane emulsification

Vladisavljević

Williams

2006

Journal of Colloid and Interface Science

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119

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A new rotating membrane emulsification system using a stainless steel membrane with 100 µm laser drilled pores was used to produce oil/water emulsions consisting of 2 wt. % Tween 20 as emulsifier, paraffin wax as dispersed oil phase and 0.01-0.25 wt. % Carbomer (Carbopol ETD 2050) as stabilizer. The membrane tube, 1 cm in diameter, was rotated inside a stationary glass cylinder, diameter of 3 cm, at a constant speed in the range 50-1500 rpm. The oil phase was introduced inside the membrane tube and permeated through the porous wall moving radially into the continuous phase in the form of individual droplets. Increasing the membrane rotational speed increased the wall shear stress which resulted in a smaller average droplet diameter being produced. For a constant rotational speed, the average droplet diameter increased as the stabilizer content in the continuous phase was lowered. The optimal conditions for producing uniform emulsion droplets were a Carbomer content of 0.1-0.25 wt. % and a membrane rotational speed of 350 rpm, under which the average droplet diameter was 105-107 µm and very narrow coefficients of variation of 4.8-4.9 %. A model describing the operation is described and it is concluded that the methodology holds potential as a manufacturing protocol for both coarse and fine droplets and capsules.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Manufacture of large uniform droplets using rotating membrane emulsification

Vladisavljević

Williams

2006

Journal of Colloid and Interface Science

Self Cite

119

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“…The latter is an irregular array of pores where the pore openings are randomly spaced on the membrane surface. Studies using the SPG membrane have suggested that the surface utilisation of this type of membrane may be as low as 1%, but with increasing injection rate this utilisation increases [15]. The low utilisation of the membrane surface area is due to the irregular and tortuous pore channels in this type of membrane, whereas the regular array type of membrane illustrated in Figure 1 has very uniform pores and pore channel depth.…”

Section: Dispersed Drop Size Modellingmentioning

confidence: 93%

“…At increasing injection rate, more and more pores will pass injected liquid [15] and the push-off force becomes significant. Hence, the size of the drops becomes defined by the push-off force and, possibly, the buoyancy force.…”

Section: Injection Rate Dependencymentioning

confidence: 99%

Membrane emulsification: Droplet size and uniformity in the absence of surface shear

Kosvintsev

Gasparini

Holdich

2008

Journal of Membrane Science

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A series of tests with membrane pore sizes between 7 and 60 microns and uniform spacing between the pores of 80 and 200 microns, conducted under conditions of zero surface shear at the membrane, show that an additional force to the buoyancy and capillary forces exists in membrane emulsification. A push-off force, derived by consideration of the geometry of the drops as they deform at the surface of the pores under high injection rates when most of the pores are passing liquid, is shown to model the size of the drops formed in the emulsification. In the tests, sunflower oil was injected into water and as the emulsification injection rate increased it was noticeable that there was a point at which the resulting drop distribution is at its narrowest. For the two pore spacings studied: 80 and 200 microns, the point at which the distribution was at its narrowest was at a Weber number of 1.5x10 -2 , where the Weber number is defined using the drop diameter rather than the pore diameter. keywords emulsification, sieve-membrane, force balance, push-off force

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“…The mean droplet/channel size ratio of 2.63 was smaller than the mean droplet/pore size ratio of 3.0 found in droplet formation from Shirasu Porous Glass (SPG) membrane within the same range of SDS concentration [32], but similar to the mean droplet/pore size ratios in membrane emulsification using asymmetric aluminium oxide membranes [33,34]. The d 3,2 value of 26.3 m is significantly smaller than the average droplet diameter of 39.1 m reported in straight-through MC emulsification for the system containing 1 wt% SDS and soybean oil using a symmetric MC plate with 10  50 m channels [25].…”

Section: Effect Of Emulsifier Content In Continuous Aqueous Phasementioning

confidence: 90%

Generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate: Effect of emulsifier and oil types

2008

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Uniform droplets of soybean oil, MCT (medium-chain fatty acid triglyceride) oil and ntetradecane with a mean diameter of 26-29 m have been generated using a silicon 24  24 mm microchip consisting of 23,489 asymmetric microchannels fabricated by photolitography and deep reactive ion etching. Each microchannel consisted of a circular 10-m diameter straight hole with a length of 70 m and a 50  10 m rectangular microslot with a depth of 30 m. At the constant oil flux of 10 Lm -2 h -1 , the percent of active channels increased with increasing the oil viscosity and ranged from 4 % for n-tetradecane to 48 % for soybean oil. The size distribution span for SDS (sodium sodium dodecyl sulphate)-and Tween 20 (polyoxyethylene (20) sorbitan monolaurate)-stabilised soybean and MCT oil droplets was 0.21-022. The ability of asymmetric microchannels to generate monodisperse soybean oil droplets at the very low SDS concentration of 0.01 wt% has been demonstrated. At the SDS concentration below the CMC, the generated droplets tend to attach to the plate surface, whereas at the higher SDS concentration they detach from the plate as soon as they are formed. The agreement between the experimental and CFD (Computational Fluid Dynamics) simulation results was excellent for soybean oil and the poorest for n-tetradecane.

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Production of O/W emulsions using SPG membranes, ceramic α-aluminium oxide membranes, microfluidizer and a silicon microchannel plate—a comparative study

Cited by 113 publications

References 20 publications

Manufacture of large uniform droplets using rotating membrane emulsification

Manufacture of large uniform droplets using rotating membrane emulsification

Membrane emulsification: Droplet size and uniformity in the absence of surface shear

Generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate: Effect of emulsifier and oil types

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