title: Superior dispersion of highly reduced graphene oxide in N,N-dimethylformamide.
abstract: Here, we report the effect of temperature on the extent of hydrazine reduction of graphene oxide in N,N-dimethylformamide (DMF)/water (80/20 v/v) and the dispersibility of the resultant graphene in DMF. The highly reduced graphene oxide (HRG) had a high C/O ratio and good dispersibility in DMF. The good dispersibility of HRGs is due to the solvation effect of DMF on graphene sheets during the hydrazine reduction, which diminishes the formation of irreversible graphene sheet aggregates. The dispersibility of the HRGs was varied from 1.66 to 0.38 mg/mL when the reduction temperature increased from 25 °C to 80 °C. The dispersibility of the HRGs was inversely proportional to the electrical conductivity of the HRGs, which varied from 17,400 to 25,500 S/m. The relationships between the C/O ratio, electrical conductivity, and dispersibility of the HRGs were determined and these properties were found to be easily controlled by manipulating the reduction temperature.
authors.affiliation: School of Chemical Engineering and Bioengineering, University of Ulsan, Namgu, Daehakro 93, Ulsan 680-749, Republic of Korea.
authors.forename: Thanh Truong
authors.initials: TT
authors.lastname: Dang
authors.forename: Viet Hung
authors.initials: VH
authors.lastname: Pham
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Hur
authors.forename: Eui Jung
authors.initials: EJ
authors.lastname: Kim
authors.forename: Byung-Seon
authors.initials: BS
authors.lastname: Kong
authors.forename: Jin Suk
authors.initials: JS
authors.lastname: Chung