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

Abstract

The combination of multi-walled carbon nanotubes (MWCNT) and carbon black (CB) is presented to produce a high-performance electrically conductive recycled additive manufacturing filament. The filament and subsequent additively manufactured electrodes were characterised by TGA, XPS, Raman, and SEM and showed excellent low-temperature flexibility. The MWCNT/CB filament exhibited an improved electrochemical performance compared to an identical in-house produced bespoke filament using only CB. A heterogeneous electrochemical rate constant, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${k}_{obs}^0$$\end{document} of 1.71 (± 0.19) × 10 ⁻³ cm s ⁻¹ was obtained, showing an almost six times improvement over the commonly used commercial conductive CB/PLA. The filament was successfully tested for the simultaneous determination of acetaminophen and phenylephrine, producing linear ranges of 5–60 and 5–200 μM, sensitivities of 0.05 μA μM ⁻¹ and 0.14 μA μM ⁻¹, and limits of detection of 0.04 μM and 0.38 μM, respectively. A print-at-home device is presented where a removable lid comprised of rPLA can be placed onto a drinking vessel and the working, counter, and reference components made from our bespoke MWCNT/CB filament. The print-at-home device was successfully used to determine both compounds within real pharmaceutical products, with recoveries between 87 and 120% over a range of three real samples. This work paves the way for fabricating new highly conductive filaments using a combination of carbon materials with different morphologies and physicochemical properties and their application to produce additively manufactured electrodes with greatly improved electrochemical performance.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00604-023-06175-2.