Graphene oxide liquid crystal domains: quantification and role in tailoring viscoelastic behavior

Md Joynul Abedin, Tanesh D. Gamot, Samuel T. Martin, Muthana Ali, Kazi Imdadul Hassan, Meysam Sharifzadeh Mirshekarloo, Rico F. Tabor, Micah J. Green, Mainak Majumder

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

Graphene oxide liquid crystals (GOLCs) were exfoliated in a wide variety of solvents (water, ethylene glycol (EG), N-methyl-2-pyrrolidone (NMP), and dimethylformamide (DMF)) by high-speed shearing of graphite oxide. Quantitative polarized light imaging of the equilibrium nematic phases of the lyotropic GOLCs gives insights into the extent of aggregation and quantifiable textural features such as domain size, d. Large nematic domains >100 μm with a high overall degree of order were obtained in water and ethylene glycol, in contrast to 5-50 μm domains in NMP and DMF at comparable volume fractions. Comprehensive rheological studies of these GOLCs indicate that larger domains correlate with higher viscosity and higher elasticity, and scaling analysis shows a power-law dependence of the Ericksen number (Er) with domain size (Er α d3.09). The improved understanding of the relationship between the microstructure and flow properties of GOLCs leads us to an approach of mixed solvent-based GOLCs as a means to tune viscoelastic properties. We demonstrate this approach for the formation of shear-aligned GOLC films for advanced flexible electronic applications such as all-carbon conductive films and thermal heaters.

Original languageEnglish
Pages (from-to)8957-8969
Number of pages13
JournalACS Nano
Volume13
Issue number8
DOIs
Publication statusPublished - 27 Aug 2019

Keywords

  • coating
  • graphene oxide
  • isotropic
  • liquid crystal domain
  • nematic
  • viscoelasticity

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