Gas Marbles: Much Stronger than Liquid Marbles

Featured in Physics
Editors' Suggestion

Gas Marbles: Much Stronger than Liquid Marbles

Yousra Timounay, Olivier Pitois, and Florence Rouyer

Phys. Rev. Lett. 118, 228001 – Published 2 June 2017

See Focus story: “Gas Marbles” Store Air in Strong Spheres

Abstract

Enwrapping liquid droplets with hydrophobic particles allows the manufacture of so-called “liquid marbles” [Aussillous and Quéré Nature (London) 411, 924 (2001); Mahadevan Nature (London)411, 895 (2001)]. The recent intensive research devoted to liquid marbles is justified by their very unusual physical and chemical properties and by their potential for various applications, from microreactors to water storage, including water pollution sensors [Bormashenko Curr. Opin. Colloid Interface Sci. 16, 266 (2011)]. Here we demonstrate that this concept can be successfully applied for encapsulating and protecting small gas pockets within an air environment. Similarly to their liquid counterparts, those new soft-matter objects, that we call “gas marbles,” can sustain external forces. We show that gas marbles are surprisingly tenfold stronger than liquid marbles and, more importantly, they can sustain both positive and negative pressure differences. This magnified strength is shown to originate from the strong cohesive nature of the shell. Those interesting properties could be exploited for imprisoning valuable or polluted gases or for designing new aerated materials.

Received 30 January 2017

DOI:https://doi.org/10.1103/PhysRevLett.118.228001

Physics Subject Headings (PhySH)

Capillary interactions Coatings Drug delivery Fracture Jamming Microfluidics

Drops & bubbles Foams Gas-liquid interfaces

Polymers & Soft Matter

Focus

“Gas Marbles” Store Air in Strong Spheres

Published 2 June 2017

A spherical shell made of plastic microspheres can store pressurized gas in a tiny volume and might be used to stabilize foams or to deliver specialized gases.

See more in Physics

Authors & Affiliations

Yousra Timounay¹, Olivier Pitois¹, and Florence Rouyer²

¹Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, ENPC ParisTech, IFSTTAR, 2 allée Kepler, 77 420 Champs-Sur-Marne, France
²Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, ENPC ParisTech, IFSTTAR, 5 boulevard Descartes, 77 454 Champs-Sur-Marne, France

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 118, Iss. 22 — 2 June 2017

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
The so-called gas marble elaborated and studied in this work. (a) Image of a gas marble ( $D_{p} = 590 μ m$ and $D_{b} = 5 mm$ ). (b) Enlargement of the particle layer (fluorescent liquid): The liquid phase can be distinguished by the curved liquid-gas interface around each particle contact. (c) Sketch of the cross section revealing the structure of the cohesive granular shell. (d) Sketch of a meniscus connecting three particles.
Reuse & Permissions
Figure 2
Side and top views of a gas marble ( $D_{p} = 315 μ m$ and $D_{b} = 6 mm$ ) during an inflation experiment for successive volume variations $Δ V$ of the gas reservoir. The relative inner pressure and side projected area are plotted versus $Δ V$ . (a) The inner pressure increases linearly with $Δ V$ , while the armor is static up to a critical pressure difference $Δ P^{+}$ . (b) A liquid fracture arises, and it is accompanied by a sudden increase of the side-view projected area, as well as a steep pressure drop from a maximum value, noted $Δ P^{+}$ , down to a plateau value, noted $Δ P^{f} \sim Δ P^{+} / 10$ . While the fracture (contour is highlighted in red) area keeps growing (b),(c), the projected area and inner pressure remain constant until the liquid film on top of the bubble ends up bursting, resulting in the release of internal pressure.
Reuse & Permissions
Figure 3
Side views of a gas marble ( $D_{p} = 250 μ m$ , $D_{b} = 10 mm$ ) during the deflation experiment for successive volume variations $Δ V$ of the gas reservoir. The relative inner pressure and side projected area are plotted versus $Δ V$ . (a)–(d) The inner pressure decreases quasilinearly with $Δ V$ down to a critical pressure difference $Δ P^{-}$ . Few pressure jumps can be observed, and they are found to be associated to small peaks of the projected area (b),(c). At the critical inner underpressure value $Δ P^{-}$ , the bubble collapses (d). Then the inner pressure value returns back steeply to atmospheric pressure, while the bubble shrinks (e).
Reuse & Permissions
Figure 4
Normalized critical overpressures ( $Δ P^{+} / Δ P_{cap}$ ) and underpressures ( $Δ P^{-} / Δ P_{cap}$ ) measured for gas marbles within both inflation and deflation conditions, respectively, as a function of bubble diameter $D_{b}$ , for several particle diameters $D_{p}$ ( $250 μ m$ , open circle; $315 μ m$ , star; $590 μ m$ , triangle). Laplace pressure $Δ P_{cap} = 8 γ / D_{b}$ is the pressure at equilibrium of the corresponding particle-free bubbles. The stability range of gas marbles is colored in gray, and it is compared to the stability range for liquid marbles and armored bubbles (dashed area [17, 18]) for which the Laplace pressure $Δ P_{cap} = 4 γ / D_{b}$ corresponds to the particle-free drop or bubbles with one liquid interface.
Reuse & Permissions

Physical Review Letters