Tunable Noble Metal Thin Films on Ga Alloys via Galvanic Replacement

Romain David, Norihisa Miki

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Room-temperature liquid metals such as GaInSn or EGaIn present the most attractive properties for soft and highly stretchable electronics. Recently, several methods have been investigated to functionalize the surface of the liquid metal via coatings and encapsulation. However, most can hardly be extended to other samples than droplets. In this study, we focus on the tunability of the process of galvanic replacement of Ga alloys with gold to form thin-film encapsulation. We characterized in-depth the obtainable composition and structure of a noble metal shell formed on the liquid metal via scanning electron microscopy, energy-dispersive X-ray, and topographic laser microscopy and highlighted the change in mechanism of galvanic replacement in different pH ranges. We showed the tunability of the surface morphology selection of different pH ranges, the solutions concentrations, and the reaction time. The adjustment of the pH of KAuBr4 solution to the preferential Ga2O3-free domain led to the successful formation of a sub-micrometer thin uniform coating with more than 60% of Au and reduced level of oxygen from 30% down to 10%. We finally demonstrated the effect of the coating composition on the electrical properties of the liquid metal using a simple and fast phase-drop measurement setup on the droplet and microchannels. A high correlation between the amount of noble metal deposited and the electrical properties of the droplets was demonstrated.

Original languageEnglish
Pages (from-to)10550-10559
Number of pages10
JournalLangmuir
Volume34
Issue number36
DOIs
Publication statusPublished - 2018 Sep 11

Fingerprint

Precious metals
liquid metals
noble metals
Liquid metals
Thin films
thin films
Encapsulation
Coatings
Electric properties
electrical properties
Shells (structures)
metal shells
laser microscopy
coatings
metal coatings
microchannels
Microchannels
Chemical analysis
reaction time
Gold

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Cite this

Tunable Noble Metal Thin Films on Ga Alloys via Galvanic Replacement. / David, Romain; Miki, Norihisa.

In: Langmuir, Vol. 34, No. 36, 11.09.2018, p. 10550-10559.

Research output: Contribution to journalArticle

David, Romain ; Miki, Norihisa. / Tunable Noble Metal Thin Films on Ga Alloys via Galvanic Replacement. In: Langmuir. 2018 ; Vol. 34, No. 36. pp. 10550-10559.
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