Additive manufacturing (AM) represents one of the nine pillars of the new industrial revolution. Owing to the enthusiastic utilization of this technology by the wider professional and amateur communities, AM is becoming a driving force in the manufacturing sector due to its fast expansion and the availability of cheap and robust 3D printers. The 3D printing, especially the fused deposition modeling (FDM) method, has previously been utilized to fabricate carbon/polylactic acid (PLA) electrodes for electrochemical setups. Such electrodes require activation from their pristine state for improved conductivity, so far achieved by chemical treatment. Herein, a new simple physical thermal annealing method to activate graphene-based PLA electrodes is presented. The graphene/PLA electrodes are fabricated via FDM 3D printing using a commercial graphene-polymer composite conductive filament and subjected to thermal and chemical activation with a subsequent electrochemical pre-treatment. The thermally annealed electrodes exhibit faster electron transfer than the chemically activated or non-treated electrodes in the inner sphere redox probe ferro/ferricyanide. The thermally activated graphene/PLA electrodes are also successfully employed as a low-cost alternative to nitroaromatic explosive sensors. This chemical-free activation method is a facile, fast, and simple route to activate conductive carbon/PLA 3D prints, which increases the electric conductivity and preserves the fine details of the printed objects, making this activation method relevant to a broad range of applied fields utilizing conductive polymer composites.

Center for Advanced Functional Nanorobots Dept of Inorganic Chemistry Faculty of Chemical Technology University of Chemistry and Technology Prague Technická 5 Prague CZ 166 28 Czech Republic

Department of Chemical and Biomolecular Engineering Yonsei University 50 Yonsei ro Seodaemun gu Seoul 03722 Korea

Future Energy and Innovation Laboratory Central European Institute of Technology Brno University of Technology Purkyňova 656 123 Brno CZ 616 00 Czech Republic

References provided by Crossref.org

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