Sustainable 3D printing of enhanced carbon nanotube-based polymeric nanocomposites: green solvent-based casting for eco-friendly electrochemical sensing applications

The current study investigates an eco-friendly solution casting method using a green solvent, Cyrene, for 3D printing polylactic acid (PLA) nanocomposites reinforced with carbon nanotubes (CNTs), for the first time. The approach which emphasizes ecological sustainability and energy efficiency, involves using a low-cost desktop fused deposition modeling (FDM) 3D printer for 3D printing of developed nanocomposite. The addition of just 3 wt.% CNTs to the polymer increased the composite electrical conductivity, from a baseline of 2.1 x 10-12 S m-1 in virgin PLA to 1.8 x 10-9 S m-1. Morphological analysis showed well-distributed CNT fillers across the filament cross-section and on the surface of the 3D printed parts. The mechanical properties of the printed samples revealed a significant improvement in tensile strength and modulus, with 22.8% and 7.41% increase, respectively. To enhance the electrical conductivity and sensing capabilities for detecting ferro/ferricyanide redox probes, an electrochemical surface activation treatment was applied to the as-printed parts. This method removed the PLA layer from the surface, exposing CNTs and improving the composite's overall performance. The successful results of this study illustrate a promising environmentally friendly approach to develop advanced nanocomposite material, based on biodegradable PLA and conductive CNTs, with the aid of low-cost 3D printing for electrochemical sensing applications.