Drop Detachment from a Micro‐Engineered Membrane Surface in a Dynamic Membrane Emulsification Process

Multiple emulsions have great potential for application in food science as a means to reduce fat content or for controlled encapsulation and release of actives. However, neither production nor stability is straightforward. Typically, multiple emulsions are prepared via two emulsification steps and a variety of approaches have been deployed to give long-term stability. It is well known that multiple emulsions can be prepared in a single step by harnessing emulsion inversion, although the resulting emulsions are usually short lived. Recently, several contrasting methods have been demonstrated which give rise to stable multiple emulsions via one-step production processes. Here we review the current state of microfluidic, polymer-stabilized and particle-stabilized approaches; these rely on phase separation, the role of electrolyte and the trapping of solvent with particles respectively.

show abstract

“…[31][32][33][34][35][36][37] Such an approach could be implemented on a large scale via, for example, dynamic membrane emulsification. 43…”

Section: Microfluidic Approachmentioning

confidence: 99%

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches

2016

View full text Add to dashboard Cite

show abstract

“…Silicon nitride and nickel membranes can be rendered hydrophilic by coating their surface with a thin layer of silicon oxide using plasma-enhanced chemical vapour deposition (PECVD) (Holzapfel et al, 2013). PECVD can also be used to decrease the pore size, while keeping the circular pore shape (Schadler and Windhab, 2006).…”

Section: Surface Modification Of Microengineered Membranesmentioning

confidence: 99%

“…Silicon membranes can be made hydrophilic via plasma oxidation in a plasma cleaner (Holzapfel et al, 2013). Silicon nitride and nickel membranes can be rendered hydrophilic by coating their surface with a thin layer of silicon oxide using plasma-enhanced chemical vapour deposition (PECVD) (Holzapfel et al, 2013).…”

Section: Surface Modification Of Microengineered Membranesmentioning

confidence: 99%

Structured microparticles with tailored properties produced by membrane emulsification

Vladisavljević

2015

Advances in Colloid and Interface Science

View full text Add to dashboard Cite

This paper provides an overview of membrane emulsification routes for fabrication of structured microparticles with tailored properties for specific applications. Direct (bottom-up) and premix (top-down) membrane emulsification processes are discussed including operational, formulation and membrane factors that control the droplet size and droplet generation regimes. A special emphasis was put on different methods of controlled shear generation on membrane surface, such as cross flow on the membrane surface, swirl flow, forward and backward flow pulsations in the continuous phase and membrane oscillations and rotations. Droplets produced by membrane emulsification can be used for synthesis of particles with versatile morphology (solid and hollow, matrix and core/shell, spherical and non-spherical, porous and coherent, composite and homogeneous), which can be surface functionalised and coated or loaded with macromolecules, nanoparticles, quantum dots, drugs, phase change materials and high molecular weight gases to achieve controlled/targeted drug release and impart special optical, chemical, electrical, acoustic, thermal and magnetic properties. The template emulsions including metal-in-oil, solid-in-oil-in-water, oil-in-oil, multilayer, and Pickering emulsions can be produced with high encapsulation efficiency of encapsulated materials and narrow size distribution and transformed into structured particles using a variety of different processes, such as polymerisation (suspension, mini-emulsion, interfacial and in-situ), ionic gelation, chemical crosslinking, melt solidification, internal phase separation, layer-by-layer electrostatic deposition, particle self-assembly, complex coacervation, spray drying, sol-gel processing, and molecular imprinting. Particles fabricated from droplets produced by membrane emulsification include nanoclusters, colloidosomes, carbon aerogel particles, nanoshells, polymeric (molecularly imprinted, hypercrosslinked, Janus and core/shell) particles, solder metal powders and inorganic particles. Membrane 2 emulsification devices operate under constant temperature due to low shear rates on the membrane surface, which range from (1−10) × 10 3 s −1 in a direct process to (1−10) × 10 4 s −1 in a premix process.Keywords: Membrane Emulsification; Polymeric microsphere; Microgel; Janus Particle; Core/Shell Particle, Colloidosome. Membrane emulsificationMembrane emulsification (ME) involves preparation of emulsions by pressing a pure dispersed phase or pre-emulsified mixture of the dispersed and continuous phase through a microporous membrane under controlled injection rate and shear conditions. In direct membrane emulsification (DME), one liquid (a dispersed phase) is injected through a microporous membrane into another immiscible liquid (the continuous phase) (Nakashima et al., 1991;, which leads to the formation of droplets at the membrane/continuous phase interface ( Figure 1a). In premix membrane emulsification (PME) (Figure 1b), a pre-emulsion is pressed through the membrane (...

show abstract

“…Changes to the pores size and morphology has been varied and shown to have a great effect on the detachment of droplets [24,25], with faster, more consistent detachment from structured uniform pores (varying slightly with shape [26]) and slower more uneven detachment from unstructured pores such as porous glass membranes [22].…”

Section: Introductionmentioning

confidence: 99%

The effects of membrane composition and morphology on the rotating membrane emulsification technique for food grade emulsions

Hancocks

Spyropoulos

Norton

2016

Journal of Membrane Science

View full text Add to dashboard Cite

a b s t r a c tThe effects of using different membrane materials and morphologies in the membrane emulsification process were observed using similar operating parameters and system geometry, allowing a direct comparison of not only the membranes themselves but also between both a stationary cross-flow membrane emulsification device and a rotated membrane emulsification device. Each membrane type tested had distinct characteristics, and the droplet sizes produced responded differently to changes in operating conditions.The rotating membrane produced similar droplet sizes to the cross flow membrane system, but at a much lower shear rate. This suggests that the detachment of the droplets occurs sooner due to the additional centrifugal force and system vibration. The Shirasu porous glass (SPG) membrane produced the smallest droplet sizes ( o1 mm from a 1 mm membrane), however the stainless steel membrane produced the lowest droplet size to pore size ratio ( $ 0.5:1) due to its cylindrical pore geometry as opposed to the tortuous geometries of the other membranes used. The droplet sizes produced at different pressures are similar between rotated and cross-flow membrane emulsification, with increases in pressure increasing droplet size and size distribution. The viscosity of the continuous phase has an effect on the droplet size; increasing the viscosity decreases the droplet size by increasing the applied shear, allowing fine tailoring of the size produced, with a more viscous continuous phase reducing the droplet size from $ 4 mm to $ 1 mm with an increase in viscosity of 100 mPa s.Rotating membrane emulsification has properties with potential to produce shear sensitive emulsion microstructures with small droplet sizes. Emulsion microstructures such as duplex emulsions, core/shell structures beads etc. can be used in the production of novel food structures.

show abstract

Drop Detachment from a Micro‐Engineered Membrane Surface in a Dynamic Membrane Emulsification Process

Cited by 12 publications

References 29 publications

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches

One-step production of multiple emulsions: microfluidic, polymer-stabilized and particle-stabilized approaches

Structured microparticles with tailored properties produced by membrane emulsification

The effects of membrane composition and morphology on the rotating membrane emulsification technique for food grade emulsions

Contact Info

Product

Resources

About