Locally sculptured modification of the electrochemical response of conductive poly(lactic acid) 3D prints by femtosecond laser processing
By Cieslik, Mateusz; Sawczak, Miroslaw; Jendrzejewski, Rafal; Celej, Joanna; Nogala, Wojciech; Ryl, Jacek
Published in Electrochimica Acta
2022
Abstract
This manuscript presents an approach to sculpture high electrochemical activity of the 3D printed electrodes with poly(lactic acid) (PLA) matrix and carbon black (CB) filler by femtosecond laser (FSL) ablation. CB-PLA utility for electrochemical applications depends on a surface modification aiming to remove the PLA and uncover the conductive CB. We have discussed how laser pulse energy is critical for such an activation process. The best performance was obtained for 4.1 J cm−2, while scanning electron microscopy (SEM) shows only partial evaporation of PLA at lower energy densities. Next, we have confirmed the efficiency of locally sculptured CB-PLA surface activation by FSL treatment, obtaining high linearity between electrochemically active surface and FSL-treated surface from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies. The electrode's efficient sculpturing of stripes 0.2 mm in width was confirmed with electrochemical microscopy (SECM). Finally, by using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, we confirmed no significant oxidation of the CB filler after FSL treatment. We revealed significant differences with ablation by longer nanosecond laser pulses, where significant heat transferred to the electrode surface contributed to partial melting and re-solidification of the PLA, negatively influencing the activation efficiency.