Galvanic Replacement of Liquid Metal/Reduced Graphene Oxide Frameworks

Abstract

have increased dramatically. [1-3] Due to the excellent electrical and mechanical properties, gallium-based LM alloys are appropriate for flexible and stretchable electrodes and circuits and have gained a wide range of potential applications, such as 3D microstructure printing, [4] soft and stretchable electronics, [5-8] and energy storage. [9] Moreover, the unique properties of bulk gallium-based LMs in chemistry have been taken more attention [2] in the areas of biomedical theranostics, [10,11] chemical catalysts, [12] and synthesis of nanostructured materials in different shapes. [13-15] Utilizing gallium-based LMs as the reaction platform, 2D metal oxide [16] and graphene [17] have been synthesized on the surface of gallium-based LMs. Based on the amalgamation of LMs, a number of gallium-based binary-metal crystals have been produced, such as CuGa 2 crystal [13] produced by the electrochemistry and GaPd crystal [14] from the Czochralski method. Meanwhile, the galvanic replacement has been introduced to form noble metal nanoparticles and nanostructured gallium-based compounds, which is a simple and promising chemical route based on the redox reaction. [15,18] On the macroscale, a variety of noble metal nanoparticles could be produced via galvanic replacements between the bulk gallium-based LMs and precursors of noble metals. [19] And the gold thin films with the tunable surface morphology were formed on the surface of bulk gallium-based LMs in different pH ranges. [20] In the nanoscale, largely because of the low melting point [19,21] and deformability, [22] ultrasonication has been widely introduced to the preparation of nanoscale LM droplets. [5,23-31] For the nanoscale LM droplets, Hoshyargar et al. [19] carried out an experiment in which the bulk LM and the Ag/Au precursors were simultaneously under sonication, and the mixture of nanorice-like particles and Ag/Au nanoparticles was obtained. The galvanic replacement reactions between the gold precursor and the submicrometer LM droplets capped with polyvinylpyrrolidone, lysozyme or sodium alginate were studied by David et al. [15] And the morphology and composition of Au-LM frameworks influenced by the reaction rates were analyzed in the different concentrations of the alkaline gold precursor solution. However, the mechanism of galvanic replacement of LM nanodroplets is not still clearly explained. The diffusion resistance of metal precursors could affect the redox reaction between the metal precursors

Applications of liquid metals in nanotechnology

“…Furthermore, EGaIn micro and nanodroplets were encapsulated by 2D graphene materials including GO, reduced GO (rGO) and functionalized GO post-synthesis or during synthesis. 139,140 In such cases, sonication of EGaIn in a GO solution resulted in EGaIn nanodroplets encapsulated with rGO and the reduction of the GO flakes were taking place at the same time. 139 Encapsulation of EGaIn nanodroplets with metal-organic frameworks (MOFs), such as ZIF-8, was also reported.…”

“…139,140 In such cases, sonication of EGaIn in a GO solution resulted in EGaIn nanodroplets encapsulated with rGO and the reduction of the GO flakes were taking place at the same time. 139 Encapsulation of EGaIn nanodroplets with metal-organic frameworks (MOFs), such as ZIF-8, was also reported. 141 The surface of LM droplets can be functionalized with micro and nanoparticles of metals, metal oxides, carbon-based and also with some organic materials, resulting in the formation of the so called 'LM marbles'.…”

Interfacial Engineering of Room Temperature Liquid Metals

“…[103] Figure 7G showed the redox between RTLMs and graphene, which can form composites to remove the heavy metal ions. [100]…”

Liquid Metal Based Flexible and Implantable Biosensors

“…The soft electrode is the primary form of liquid metal in resistant and capacitive sensors. Moreover, there is ongoing research for more forms of liquid metal, for example, liquid metal particles are showing promise, possessing several notable attributes [ 128 , 129 ]. They are easily fabricated and have a unique metal-oxidation structure and the deformable ability to merge, self-healed, and transform, which enables their useful application in composites, soft electronics, and microfluidic, and so on.…”