| 초록 |
The liquid-phase exfoliation (LPE) of graphite is a cost-effective method for producing graphene flake (GF) dispersion. However, there are several drawbacks of the LPE such as low GF concentrations (i.e. yields)and long process time, which hampers its scalability in the industries. To overcome these issues, shear-based LPE gains more interest. Here, we report the effects of temperature in shear-exfoliated GF in N-methyl-2-pyrrolidone (NMP). The concentration of GF increased from 0.14 to 0.42 mg/ml by reducing the exfoliation temperature from 293 to 263 K, respectively, which is attributed to the changes in solvent polarity, surface tension, and viscosity. Remarkably, the shear-based LPE requires a shorter operation time (< 20 min) and the resultant GF showed a lower defect density compared to the sonication-exfoliated GF reported in the literature. The results provide a guide for shear-based LPE to achieve a higher concentration of GF dispersion in organic solvents. |
