Effect of Core Liquid Surface Tension on the Liquid Marble Shell

Abstract

surface tension gradient, [24,25] magnetic field, [26-29] electric field, [30-34] mechanical force, [4,35] and pH. [36-38] The porous liquid marble shell enables gas exchange, which allows it to serve as a gas sensor, [39,40] a microreactor for gas-phase reactions, [41,42] a carbon dioxide capturing tool, [43] as well as a cell culture platform. [15,44,45] The behavior and the structure of a liquid marble shell depends on the preparation method, morphology of the encapsulating particles, and the properties of the core liquid. This paper investigates the relationship between the core liquid and the properties of the shell. A liquid marble shell represents a flexible superhydrophobic surface analogous to Cassie-Baxter wetting. [46] The shell consists of encapsulating particles and pores that prevent direct contact between the core liquid and the carrying substrate. There are only a few works in available literature that show the structure of a liquid marble shell. [12,47,48] Notable are the observations by Aussillous et al. [12] and Bormashenko et al. [48] using an optical microscope and environmental scanning electron microscope, respectively. Both studies revealed the existence of interparticle gaps at the surface of a liquid marble. Lin et al. investigated the shell of a liquid marble with an optical microscope. [49] The team reported that a liquid marble shell is not fully covered with particles. Furthermore, the pores on the shell cause liquid marbles to evaporate. [50] Nguyen et al. investigated on the shell structure using a confocal microscope. [47] The team showed that fine particles are packed in between coarse particles within the shell. The particles at the innermost layer of the shell always penetrate the core liquid. [47] Wang et al. reported that the extent of penetration depends on the surface tension of the core liquid. [51] A reduction in the surface tension of the core liquid increased the penetration into it and decreased the lifetime. Prior works discuss only on the structure of the shell. There has yet to be a detailed study on the properties of the shell in response to the core liquid surface tension. The integrity of a liquid marble depends on the properties of the shell. Therefore, it is essential to study the behavior of the shell to understand its effects on both the static and the dynamic properties of a liquid marble. Our present work investigates the effect of the surface tension of the core liquid on the shell. The surface tension was controlled using known quantities of surfactant. Shell thickness decreased with the surface

Controllable high-performance liquid marble micromixer

“…In other words, the deformation is either (i) transient during the angular acceleration or (ii) constant during the stable spinning state. 65 As such, the effect of deformation on the internal flow of a spinning liquid marble is negligible.…”

Oscillation-Induced Mixing Advances the Functionality of Liquid Marble Microreactors

“…Several promising results include cell spheroid generation, − in situ stem cell differentiation, molecular-level electrochemical analysis, large carbon microsphere synthesis, and adhesive storage and release, among others. To facilitate the application of LMs, recent research efforts have aimed to automate their production, − slow their evaporation, increase their transparency, − and promote mixing. , In particular, it is crucial but difficult to attain sufficient mixing in an LM.…”

Investigation of liquid marble shell using X‐ray: shell thickness and effective surface tension

“…Attractive features of a liquid marble such as low evaporation rate, high robustness, tuneable porosity, and ease of manipulation enable it to be an efficient tool for microfluidic applications [2–11] . These features depend on the properties and structure of the liquid marble shell [12–14] . Recent works on liquid marble have been devoted to understanding its shape, stability, crystallization, and microfluidic applications [15–24] .…”

“…A liquid marble shell consists of encapsulating particles and pores that prevent direct contact between the core liquid and the carrying substrate. The distribution of the encapsulating particles and the pores depends on particle size, [12,24–26] particle type, [13,20,22,27] core liquid, [14,16,28] and preparation method [19,29–32] . Several researchers attempted to observe the structure of a thin shell using interfacial polymerization and conventional microscopy techniques.…”