Production of Particle‐Stabilized Nonspherical Emulsion Drops in Simple Shear Flow

Abstract

Nonspherical drops are of interest in the formation of microcapsules in life sciences like food, pharmacy, and cosmetics, agro and fine chemicals as well as material sciences. Out of many systems, particle-stabilized emulsion drops, so-called Pickering emulsions, exhibit an interesting formulation. Systems with Pickering particles applied in an excess amount were investigated. During deformation, the particles fully covered the enlarged drop interfaces and prevented its relaxation to a spherical drop shape. Nonspherical drops could be produced in simple shear flow using an adequate process routine. The production in a simple device is a promising high-throughput alternative to microfluidic devices.

Biopolymer-based particles as stabilizing agents for emulsions and foams

“…Jamming of hard particles at the interface 144 generates an elastic monolayer of high rigidity. During emulsion formation, one consequence 145 of this interfacial particle jamming is the possibility to produce distinctly non-spherical 146 droplets when liquid droplets deformed by the applied shear field are prevented from relaxing 147 back to the normal equilibrium spherical shape (Merkel et al, 2015).…”

Influence of Preparation Method on Size Distribution of the Dispersed Phase of Primary Emulsions

“…Analyzing the influence of rotational impeller speed, both standard mixer and homogenizer, on the size of dispersed‐phase droplets, the reduction of the dispersed‐phase droplet size was noted only in the case of the mixer, for all investigated water phases. The effect of the homogenizer rotational speed on the dispersed‐phase droplet size was complex and closely connected with the water phase viscosity, as demonstrated in our earlier publications 17, 18.…”

“…8) and the maximum stable droplet in shear or viscous area d v (Eq. 10), it can be established that d v ≈ λ 0 ≈ d max , so under the studied conditions the size of the droplets is influenced both by inertial and viscosity forces 18, 29. …”

“…8, which is the basic relationship between the forces acting on the droplet. Its size is a result of the equilibrium between the tearing stresses and stabilization forces and depends on the continuous‐phase density, interfacial tension, and mean speed of energy dissipation 18, 26, 27. …”

Mechanics of Pickering Drops Probed by Electric Field–Induced Stress

“…External stresses can be applied by various means to study the mechanical and rheological properties of Pickering drops. Buckling has been measured by drop volume compression and expansion [ 15 , 16 , 17 ], and drop deformation and elasticity have been investigated by mechanical compression [ 18 , 19 , 20 ], hydrodynamic shear flow [ 21 , 22 ], and microfluidic focusing devices [ 23 ].…”