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Emerging applications of liquid metals featuring surface oxides.

Dickey MD - ACS Appl Mater Interfaces (2014)

Bottom Line: Despite these desirable properties, applications calling for liquid metal often use toxic mercury because gallium forms a thin oxide layer on its surface.The oxide interferes with electrochemical measurements, alters the physicochemical properties of the surface, and changes the fluid dynamic behavior of the metal in a way that has, until recently, been considered a nuisance.Here, we show that this solid oxide "skin" enables many new applications for liquid metals including soft electrodes and sensors, functional microcomponents for microfluidic devices, self-healing circuits, shape-reconfigurable conductors, and stretchable antennas, wires, and interconnects.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States.

ABSTRACT
Gallium and several of its alloys are liquid metals at or near room temperature. Gallium has low toxicity, essentially no vapor pressure, and a low viscosity. Despite these desirable properties, applications calling for liquid metal often use toxic mercury because gallium forms a thin oxide layer on its surface. The oxide interferes with electrochemical measurements, alters the physicochemical properties of the surface, and changes the fluid dynamic behavior of the metal in a way that has, until recently, been considered a nuisance. Here, we show that this solid oxide "skin" enables many new applications for liquid metals including soft electrodes and sensors, functional microcomponents for microfluidic devices, self-healing circuits, shape-reconfigurable conductors, and stretchable antennas, wires, and interconnects.

No MeSH data available.


Related in: MedlinePlus

Oxide skin that formson alloys of gallium has a yield stress. (a) It can be measured byplacing a thin sample (∼1 mm thick) of the metal between aparallel plate rheometer. The oxide spans the periphery between thetwo plates. (b) Beyond a critical surface yield stress (∼0.5–0.6N/m), the oxide breaks and the metal flows readily. Below the surfaceyield stress, the oxide skin is elastic and mechanically stabilizing.Adapted with permission from ref (23). Copyright 2008 Wiley.
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fig2: Oxide skin that formson alloys of gallium has a yield stress. (a) It can be measured byplacing a thin sample (∼1 mm thick) of the metal between aparallel plate rheometer. The oxide spans the periphery between thetwo plates. (b) Beyond a critical surface yield stress (∼0.5–0.6N/m), the oxide breaks and the metal flows readily. Below the surfaceyield stress, the oxide skin is elastic and mechanically stabilizing.Adapted with permission from ref (23). Copyright 2008 Wiley.

Mentions: Figure 2a is a depiction of one such experiment where anoscillating top plate and a stationary bottom plate sandwich a sampleof EGaIn. Because the bulk viscosity of the metal is low, the oxidedominates the mechanical resistance to oscillation of the top plate.Increasing the amplitude of oscillations at constant frequency allowsfor the extraction of stress–strain relationships of the oxideand thus, the mechanical properties of the oxide. Figure 2b plots the surface elastic modulus versus surfacestress. Below a critical yield surface stress (∼0.5–0.6N/m), the skin is elastic and stable, which is critical for patterningthe metal into nonequilibrium shapes. Above the critical yield stress,the skin ruptures and the metal flows readily.


Emerging applications of liquid metals featuring surface oxides.

Dickey MD - ACS Appl Mater Interfaces (2014)

Oxide skin that formson alloys of gallium has a yield stress. (a) It can be measured byplacing a thin sample (∼1 mm thick) of the metal between aparallel plate rheometer. The oxide spans the periphery between thetwo plates. (b) Beyond a critical surface yield stress (∼0.5–0.6N/m), the oxide breaks and the metal flows readily. Below the surfaceyield stress, the oxide skin is elastic and mechanically stabilizing.Adapted with permission from ref (23). Copyright 2008 Wiley.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231928&req=5

fig2: Oxide skin that formson alloys of gallium has a yield stress. (a) It can be measured byplacing a thin sample (∼1 mm thick) of the metal between aparallel plate rheometer. The oxide spans the periphery between thetwo plates. (b) Beyond a critical surface yield stress (∼0.5–0.6N/m), the oxide breaks and the metal flows readily. Below the surfaceyield stress, the oxide skin is elastic and mechanically stabilizing.Adapted with permission from ref (23). Copyright 2008 Wiley.
Mentions: Figure 2a is a depiction of one such experiment where anoscillating top plate and a stationary bottom plate sandwich a sampleof EGaIn. Because the bulk viscosity of the metal is low, the oxidedominates the mechanical resistance to oscillation of the top plate.Increasing the amplitude of oscillations at constant frequency allowsfor the extraction of stress–strain relationships of the oxideand thus, the mechanical properties of the oxide. Figure 2b plots the surface elastic modulus versus surfacestress. Below a critical yield surface stress (∼0.5–0.6N/m), the skin is elastic and stable, which is critical for patterningthe metal into nonequilibrium shapes. Above the critical yield stress,the skin ruptures and the metal flows readily.

Bottom Line: Despite these desirable properties, applications calling for liquid metal often use toxic mercury because gallium forms a thin oxide layer on its surface.The oxide interferes with electrochemical measurements, alters the physicochemical properties of the surface, and changes the fluid dynamic behavior of the metal in a way that has, until recently, been considered a nuisance.Here, we show that this solid oxide "skin" enables many new applications for liquid metals including soft electrodes and sensors, functional microcomponents for microfluidic devices, self-healing circuits, shape-reconfigurable conductors, and stretchable antennas, wires, and interconnects.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States.

ABSTRACT
Gallium and several of its alloys are liquid metals at or near room temperature. Gallium has low toxicity, essentially no vapor pressure, and a low viscosity. Despite these desirable properties, applications calling for liquid metal often use toxic mercury because gallium forms a thin oxide layer on its surface. The oxide interferes with electrochemical measurements, alters the physicochemical properties of the surface, and changes the fluid dynamic behavior of the metal in a way that has, until recently, been considered a nuisance. Here, we show that this solid oxide "skin" enables many new applications for liquid metals including soft electrodes and sensors, functional microcomponents for microfluidic devices, self-healing circuits, shape-reconfigurable conductors, and stretchable antennas, wires, and interconnects.

No MeSH data available.


Related in: MedlinePlus