Generation and Analysis of Axiolitic Liquid‐Metal Droplets in a T‐Junction Microfluidic Device

Abstract

Liquid metals like the eutectic gallium-indium (EGaIn) alloys are fantastic materials for producing micro-droplets. In this work, polyethylene glycol (PEG) and deionized (DI) water were chosen as the continuous phase, and EGaIn is the dispersed phase to generate spherical and non-spherical (axiolitic) droplets in a T-junction microfluidic device. Especially for axiolitic droplets, a systematic investigation on the relation of their sizes and flow features was done. A general formula as a function of both the flow rate Q c of the continuous phase and the flow-rate ratio R(Q c /Q d ) is given to fit all the experimental data. Furthermore, effects of the viscosity of the continuous phase on the droplet size, size distribution and hydrodynamic regimes are also discussed. When the viscosity gets higher, the general droplet size gets smaller, the zone for generating axiolitic droplets becomes narrower, and the size distribution of the droplets is relatively worse. These are all because the correlation among the viscosity, the oxide layer on the droplet interface and the droplet morphology. The higher the viscosity is, the thinner the oxide layer is, and the less mechanical stability the droplets would have. The results of axiolitic droplets of liquid metals have wide potential applications in microfluidics, electronics, thermal probe and so on, since the axiolitic droplets are anisotropic compared to the spherical.[a] T.

Controllable Enhancement of Capsule‐Membrane Wrinkles by Flow Shear and Preparation of Double‐Layer Polyamide Microcapsules

“…The slowing down mass transfer results in a slower growth of membrane. Under the larger shear force, the thinner membrane is more likely to deform to generate wrinkled microcapsules …”

Preparation of Polyurea Microcapsules Containing Phase Change Materials Using Microfluidics

“…This device is simple in the fabrication and operation, and is expected to have more applications for other materials, such as liquid metals . The uniform liquid‐metal droplets with spherical or axiolitic shapes have been fabricated through the microfluidic device …”

Generation of Nonspherical Liquid Metal Microparticles with Tunable Shapes Exhibiting an Electrostatic-Responsive Performance

“…In previous studies, the formation of shaped NLMs usually follows a similar strategy, trying to split bulk LMs into microparticles, shape them by external geometrical constraints, and stabilize morphologies by the formed oxide layer. Such approaches relying on external geometric restriction to form shaped NLMs have the limitations of low efficiency, low throughput, and low morphology optionality. , There are still many challenges in the preparation of shaped NLMs, which also limit their practical applications.…”

“…7,16 Prefabricated templates or microfluidic channels are usually used to mold LMs into specific shapes. 16,17,33,34 In the case of metal part casting, crimson molten metal is poured into a mold of particular shapes and left to cool for solidification. In previous studies, the formation of shaped NLMs usually follows a similar strategy, trying to split bulk LMs into microparticles, shape them by external geometrical constraints, and stabilize morphologies by the formed oxide layer.…”

“…Such approaches relying on external geometric restriction to form shaped NLMs have the limitations of low efficiency, low throughput, and low morphology optionality. 34,35 There are still many challenges in the preparation of shaped NLMs, which also limit their practical applications.…”