Methods for preparation of concentrated graphene ink compositions and related composite materials
A rapid, scalable methodology for graphene dispersion and concentration with a polymer-organic solvent medium, as can be utilized without centrifugation, to enhance graphene concentration.
1. A method of preparing an inkjet printed graphene ink composition, said method comprising:
exfoliating a graphene source material with a medium comprising an organic solvent selected from ethanol and dimethylformamide, and an ethyl cellulose;
contacting at least a portion of said exfoliated graphene medium with an aqueous medium to concentrate exfoliated graphene and ethyl cellulose in a solid precursor composition comprising graphene and a said ethyl cellulose;
isolating said solid composition from said exfoliating and said aqueous media;
contacting said solid graphene-ethyl cellulose precursor composition with a hydrophobic fluid component, to provide a graphene ink composition;
inkjet printing said graphene ink composition on a substrate; and
photonic annealing said graphene ink composition.
2. The method of claim 1 wherein said hydrophobic fluid comprises a component selected from terpenes, terpine alcohols and combinations thereof.
3. The method of claim 1 wherein said hydrophobic fluid component comprises a terpineol and cyclohexanone.
4. The method of claim 1 wherein said graphene ink composition has a graphene concentration of greater than about 3 mg/mL.
5. The method of claim 4 wherein said graphene ink composition has a graphene concentration of about 20 mg/mL.
6. The method of claim 5 wherein said graphene ink has a solids content of about 4% w/v.
7. The method of claim 6 wherein said graphene ink composition has a viscosity of about 8-15 mPa·sec.
8. The method of claim 1 wherein said exfoliating comprises shear mixing said graphene source material and said medium.
9. A method of preparing an inkjet printed graphene ink composition, said method comprising:
exfoliating a graphene source material with a medium comprising an organic solvent selected from ethanol and dimethylformamide, and an ethyl cellulose to provide a precursor composition comprising graphene and a said ethyl cellulose;
isolating said precursor composition from said exfoliating and said aqueous media;
contacting said graphene-ethyl cellulose precursor composition with a hydrophobic fluid component, to provide a graphene ink composition comprising a graphene concentration greater than about 3 mg/mL;
inkjet printing said graphene ink composition on a substrate; and
photonic annealing said graphene ink composition.
10. The method of claim 9 wherein said hydrophobic fluid comprises a component selected from terpenes, terpine alcohols and combinations thereof.
11. The method of claim 9 wherein said hydrophobic fluid component comprises a terpineol and cyclohexanone.
12. The method of claim 9 wherein said graphene ink composition has a graphene ink concentration of about 20 mg/mL.
13. The method of claim 12 wherein said graphene ink has a solids content of about 4% w/v.
14. The method of claim 13 wherein said graphene ink composition has a viscosity of about 8-15 mPa·sec.
15. The method of claim 9 wherein said exfoliating comprises shear mixing said graphene source material and said medium.
16. A method of using photonic annealing to prepare a graphene ink composite, said method comprising:
exfoliating a graphene source material with a medium comprising an organic solvent selected from ethanol and dimethylformamide, and an ethyl cellulose to provide a precursor composition comprising graphene and a said ethyl cellulose;
isolating said precursor composition from said exfoliating and said aqueous media;
contacting said graphene-ethyl cellulose precursor composition with a hydrophobic fluid component, to provide a graphene ink composition comprising a solids content of about 4% w/v, a graphene concentration of about 20 mg/mL and a viscosity of about 8-about 15 mPa·sec;
inkjet printing said graphene ink composition on a substrate to provide a graphene-substrate composite; and
photonic annealing said graphene ink composition to provide a graphene ink composition comprising a decomposition product of a said ethyl cellulose.
17. The method of claim 16 wherein said hydrophobic fluid component comprises a terpineol and cyclohexanone.
18. The method of claim 16 wherein said precursor composition comprises about 50% wt. graphene and about 50% wt. a said ethyl cellulose.