title: Tailoring Graphene Nanosheets for Highly Improved Dispersion Stability and Quantitative Assessment in Nonaqueous Solvent.
abstract: Aggregation is a critical limitation for the practical application of graphene-based materials. Herein, we report that graphene oxide (GO) nanosheets chemically modified with ethanolamine (EA), ethylene glycol (EG), and sulfanilic acid (SA) demonstrate superior dispersion stability in organic solvents, specifically EG, based on the differences in their covalent chemistries. Functionalized GO was successfully dispersed in EG at a concentration of 9.0 mg mL(-1) (0.50 vol %), the highest dispersion concentration reported to date. Moreover, our study introduces a unique analytical method for the assessment of dispersion stability and successfully quantifies the instability index based on transmission profiles under centrifugation cycles. Interestingly, GO-EG and GO-EA exhibited highly improved dispersion stabilities approximately 96 and 48 times greater than that of GO in EG solvent, respectively. This finding highlights the critical role of surface functional groups in the enhancement of chemical affinity and miscibility in the surrounding media. We anticipate that the novel structural designs and unique tools presented in this study will further the understanding and application of chemically functionalized carbon materials.
authors.forename: Minju
authors.initials: M
authors.lastname: Park
authors.affiliation: Central Advanced Research & Engineering Institute, Hyundai Motor Company , Uiwang 16082, Korea.
authors.forename: Kyonghwa
authors.initials: K
authors.lastname: Song
authors.forename: Taemin
authors.initials: T
authors.lastname: Lee
authors.affiliation: Central Advanced Research & Engineering Institute, Hyundai Motor Company , Uiwang 16082, Korea.
authors.forename: JinHyeok
authors.initials: J
authors.lastname: Cha
authors.affiliation: Central Advanced Research & Engineering Institute, Hyundai Motor Company , Uiwang 16082, Korea.
authors.forename: InWoong
authors.initials: I
authors.lastname: Lyo
authors.forename: Byeong-Su
authors.initials: BS
authors.lastname: Kim
keywords: covalent functionalization; dispersion stability; ethylene glycol; graphene oxide; quantitative assessment