Exploring Different Carbon Allotrope Thermoplastic Composites for Electrochemical Sensing

Abstract

Composite electrodes are an effective and cheap way to utilize a wide range of carbon materials to make electrodes. More recently, thermoplastics have been widely used as the binder to make carbon composite electrodes, as varying fabrication approaches, such as three-dimensional (3D) printing, can make highly reproducible electrodes. However, there is a clear need to understand how the electrochemical performance of different carbon allotrope materials varies when made into sensors. We accessed poly(lactic acid) (PLA) thermoplastic filaments containing carbon black, graphite, graphene, multiwall carbon nanotube (MWCNT), and carbon fiber using various electrochemical techniques. Graphite/PLA and graphene/PLA electrodes showed the best electron transfer kinetics. Graphene/PLA electrodes had the greatest sensitivity and lowest limit of detection for the measurement of serotonin. CB/PLA was least prone to electrode fouling from oxidative by-product generated from the oxidation of serotonin. 3D printing was used to make various carbon allotrope materials into complex shapes to evaluate the batch uniformity of the printed parts. Of all the materials explored, CB/PLA had the best resolution and batch uniformity when compared with PLA. Overall, our study highlights that the type of carbon allotrope has as much influence as the amount of carbon on the electrochemical performance of carbon thermoplastic electrodes. These findings will provide significant guidance on the appropriate choice of carbon thermoplastic composite materials when designing electrodes for a wide range of applications.

3D-Printed Microelectrodes for Biological Measurement

“…We explored the relationship between electrode length and conductivity using 100 μm print layer thickness strands. CB/PLA microelectrodes were more conductive than MWCNT/PLA microelectrodes, which is expected, as we have previously shown that there is three times more carbon content within the CB/PLA filament Figure A shows that following printing of the filament, conductivity was significantly reduced for strands that were 0.5 mm when compared to 3 mm in length ( p < 0.05, n = 6).…”

Preprinting Saponification of Carbon Thermoplastic Filaments Provides Ready-to-Use Electrochemical Sensors

“…We have previously shown that MWCNT/PLA filaments are highly resistive and struggle to generate functional electrochemical sensors due to the very small carbon load within the filament . Therefore, we explored the impact of our saponification approach on the MWCNT/PLA electrodes.…”

“…A solution to these challenges has been to utilize 3D printing as a means of providing a simple and precise approach to the production of carbon composite thermoplastics electrodes. − The popularity of 3D printing to make electrochemical sensors has surged recently due to the accessibility and simplicity of this manufacturing approach, , the ability to make complete analytical measurement devices, − and the availability of a wide array of conductive carbon thermoplastic materials. − …”

Multi-walled carbon nanotubes/carbon black/rPLA for high-performance conductive additive manufacturing filament and the simultaneous detection of acetaminophen and phenylephrine

“…This form of AM has found substantial use within electrochemical research due to the overall low cost of entry and consumables. There is an increasing range of conductive filaments available commercially utilising different carbon allotropes [ 2 ], with the most widely used based on carbon black (CB) within poly(lactic acid) (PLA) [ 3 ]. A large amount of work has been reported on improving the performance of the commercial conductive PLA through either changing the printing parameters, such as printing speed [ 4 – 6 ] or enhancing the surface of the additively manufactured electrode through “activation” [ 7 ].…”