Direct exfoliation of layered materials in low-boiling point solvents using weak acid salts

Yoshihiko Arao, Jonathon D. Tanks, Masatoshi Kubouchi, Akira Ito, Atsushi Hosoi, Hiroyuki Kawada

Research output: Contribution to journalArticle

Abstract

The method for mass production of nanosheets is essential for fully realizing their commercial use. Direct exfoliation of layered materials in liquid is the simplest and low-cost technique for exfoliation without introducing defects in basal plane. However, the technique requires toxic and high-boiling point solvents, which makes it difficult for further processing. In addition, solvent exchange involves time-consuming processes such as filtering and redispersion. A breakthrough is necessary to make 2D-crystal-based functional dispersions. Here, we find a new method to directly exfoliate layered materials in low-boiling point solvents. Addition of small amounts of salt prevents reaggregation of exfoliated nanosheets and improves electrical repulsion. In this process, the mechanical force applied by sonication generates active carbon species at the fractured surfaces, leading to a reaction between the active carbon and the salt in liquid. High concentration graphene dispersions (1 g/L) can be obtained in isopropanol with only 5 min of sonication. We also confirm salt-assisted exfoliation is effective for the other 2D crystals such as MoS2 and boron nitride in a wide variety of polar solvents. Direct exfoliation in processable solution opens up a range of large-area applications such as high performance nanocomposites and coatings.

LanguageEnglish
Pages261-268
Number of pages8
JournalCarbon
Volume142
DOIs
Publication statusPublished - 2019 Feb 1

Fingerprint

Boiling point
Salts
Acids
Sonication
Nanosheets
Dispersions
Carbon
Crystals
Graphite
2-Propanol
Boron nitride
Poisons
Liquids
Graphene
Ion exchange
Nanocomposites
Coatings
Defects
Processing
Costs

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

Cite this

Direct exfoliation of layered materials in low-boiling point solvents using weak acid salts. / Arao, Yoshihiko; Tanks, Jonathon D.; Kubouchi, Masatoshi; Ito, Akira; Hosoi, Atsushi; Kawada, Hiroyuki.

In: Carbon, Vol. 142, 01.02.2019, p. 261-268.

Research output: Contribution to journalArticle

Arao, Yoshihiko ; Tanks, Jonathon D. ; Kubouchi, Masatoshi ; Ito, Akira ; Hosoi, Atsushi ; Kawada, Hiroyuki. / Direct exfoliation of layered materials in low-boiling point solvents using weak acid salts. In: Carbon. 2019 ; Vol. 142. pp. 261-268.
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