Electrosynthesis and characterization of poly(rhodamine B) coatings on 3d printed polylactic acid doped carbon black (PLA-CB) electrodes for promising sensor applications

Conductive filament-based polylactic acid doped carbon black (PLA-CB) was used as an alternative to metal-based electrodes. Rhodamine B (RhB) was electrochemically polymerized on PLA-CB. The electrosynthesis of poly(rhodamine B) (PRhB) was achieved by cyclic voltammetry, galvanostatic, and potentiostatic techniques. PRhB coatings were characterized to investigate their morphology, chemical, and optical properties using different microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV-visible spectrophotometry (UV-vis). The theoretical UV-vis spectrum calculated with the Time-Dependent Density Functional Theory (TD-DFT) method was comparable with experimental UV-vis spectra. The modified electrode was tested for the detection of melatonin, gallic acid, dopamine, and nitrite showing an enhanced performance. The obtained results are promising for developing adherent PRhB coatings and can be used as a sensor in future studies. 3D printed conductive electrodes can be inexpensively manufactured in electrochemical laboratories using PLA-CB and reach properties well comparable to those obtained at conventional carbon or metallic electrodes, hence used for RhB polymerization.

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