Lignin-assisted carbon nanotube dispersion for conductive ink application

Abstract

The poor dispersibility of multi-walled carbon nanotubes (MWCNT) in water is a serious obstacle towards development of water-based conductive ink. Therefore, the addition of tertiary phase became necessary to promote such dispersion. In this work, MWCNT ink was synthesized using alkali lignin (AL) as a dispersing agent and water as a solvent. UV-Visible analysis and zeta potential measurement were used to assess the dispersion degree and stability of the alkali lignin-coated MWCNT (AL/MWCNT) by varying the concentration of AL from 0.1 to 1.0 ppm. Field Emission Scanning Electron Microscope (FESEM) was used to visualize the morphology of AL/CNT ink. Results obtained strongly suggest that MWCNT ink containing approximately 0.5 - 0.8 ppm of AL reduced the size of MWCNT agglomerates and promoted good dispersibility and long-term stability of the ink. AL concentration above or below this value will destabilize the system. This ink has a great potential for many printed electronics applications, such as flexible display systems, sensors, photovoltaic cells, and radio frequency identification.