The effects of different plasticisers on the electrochemical performance of bespoke conductive additive manufacturing filaments using recycled PLA

In this work, we report the production, physicochemical, electrochemical, and electroanalytical characterisation of 10 different bespoke additive manufacturing filaments that utilise different chemicals as plasticisers. The inclusion of a plasticiser within a recycled poly(lactic acid) based additive manufacturing filament produced through thermal mixing is required when incorporating high loadings of conductive fillers. All 10 chemicals used in this work acted as suitable plasticisers for producing conductive filaments, allowing the incorporation of 25 wt% carbon black with 65 wt% recycled poly(lactic acid) whilst ensuring excellent low-temperature flexibility and printability. The surfaces of the additive manufactured electrodes were characterised before and after electrochemical activation, revealing a significant increase in the amount of graphitic carbon present after activation in all cases. Through electrochemical characterisation against [Ru(NH₃)₆]³⁺ and [Fe(CN)₆]^4-, as well as through the electroanalytical detection of dopamine, castor oil, tris(2-ethylhexyl) trimellitate, and poly(ethylene glycol) were identified as the best overall performing plasticisers for the production of additively manufactured electrodes.