Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces: extrusion and characterisation of filaments for improved 3D-printed surfaces

Abstract

A new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added as fillers in poly(lactic acid) (PLA)-based composites to extrude 3D filaments. Carbon black served as a primary filler to reach high composite conductivity at low diamondised nanocarbon concentrations (0.01 to 0.2 S/cm, depending on the type and amount of filler). The aim was to thoroughly describe and understand the interactions between the composite components and how they affect the rheological, mechanical and thermal properties, and electrochemical characteristics of filaments and material extrusion printouts. The electrocatalytic properties of composite-based electrodes, fabricated with a simple 3D pen, were evaluated using multiple electrochemical techniques (cyclic and differential pulse voltammetry and electrochemical impedance spectroscopy). The results showed that the addition of 5 wt% of any of the diamond-rich nanocarbons fillers significantly enhanced the redox process kinetics, leading to lower redox activation overpotentials compared with carbon black–loaded PLA. The detection of dopamine was successfully achieved through fabricated composite electrodes, exhibiting lower limits of detection (0.12 μM for DND and 0.18 μM for BCNW) compared with the reference CB-PLA electrodes (0.48 μM). The thermogravimetric results demonstrated that both DND and BCNW powders can accelerate thermal degradation. The presence of diamondised nanocarbons, regardless of their type, resulted in a decrease in the decomposition temperature of the composite. The study provides insight into the interactions between composite components and their impact on the electrochemical properties of 3D-printed surfaces, suggesting electroanalytic potential. Graphical abstract

Elucidating Charge Transfer Processes and Enhancing Electrochemical Performance of Laser-Induced Graphene via Surface Engineering with Sustainable Hydrogel Membranes: An Electrochemist's Perspective

“…1c, confirms the presence of such an Ohmic drop. Similar cases may be observed for conductive 3D-printed composites [49].…”

Microwave-Induced Processing of Free-Standing 3D Printouts: An Effortless Route to High-Redox Kinetics in Electroanalysis

“…Due to its origin and decomposition patterns, it has been classified as a biodegradable, compostable green polymer [ 12 ] and is thus considered a sustainable material. Filling PLA with conductive nanoparticles beyond a certain percolation threshold (typically 15% [ 13 ]) allows for 3D-printable conductive composites to be obtained. The manufacturing cost of a single electrode using this technology is very low (0.05 USD), providing an attractive alternative to other electrodes typically used in the electrochemical analysis, including the commercially available Proto-Pasta ® [ 14 , 15 , 16 , 17 , 18 , 19 ] and Black Magic 3D ® electrodes [ 20 , 21 , 22 ].…”