Carbon nanotube-cellulose ink for rapid liquid identification

Abstract

In this work, a conductive ink based on micro fibrillated cellulose (MFC) and multi-walled carbon nanotubes (MWCNT) was used to produce transducers for rapid liquid identification. The transducers are simple resistive devices that can be easily fabricated by scalable printing techniques. We monitored the electrical response due to the interaction between a given liquid with the carbon nanotube-cellulose film over time. Using principal component analysis of the electrical response, we were able to extract robust data used to differentiate several liquid categories. We show that the proposed liquid sensor can classify different liquid systems, including organic solvents (e.g., acetone, chloroform, and alcohol) and is also able to differentiate low concentrations of glycerin in water (10-100 ppm). We have also investigated the influence of two vital liquid properties: dielectric constant and vapor pressure on the physical transduction mechanisms of MFC-MWCNT sensors, which were corroborated by independent heat flow measurements (thermogravimetric analysis). The proposed MFC-MWCNT sensor platform may help paving the way to rapid, inexpensive, and robust liquid analysis and identification.