The role of the electrolysis and enzymatic hydrolysis in the enhancement of the electrochemical properties of 3D-printed carbon black/poly(lactic acid) structures

TL;DR

This study explores how electrolysis and enzymatic hydrolysis can enhance the electrochemical properties of 3D-printed carbon black/poly(lactic acid) structures, leading to more efficient activation protocols for electrochemical applications.

Contribution

It introduces a novel combined activation method using electrolysis and enzymatic hydrolysis to improve surface electroactivity of 3D-printed CB-PLA structures.

Findings

Electrolysis and enzymatic hydrolysis modify surface chemistry and improve electron transfer.

Electrolysis accelerates PLA hydrolysis and enhances charge transfer kinetics.

Surface electropolymerization is key to activation, not synergistic enzymatic-electrolysis interaction.

Abstract

Additive manufacturing, called 3D printing, starts to play an unprecedented role in developing many applications in industrial or personalized products. The conductive composite structures require additional treatment to achieve an electroactive surface useful for electrochemical devices. In this paper, the surfaces of carbon black/poly(lactic acid) CB-PLA printouts were activated by electrolysis or enzymatic digestion with proteinase K, or a simultaneous combination of both. Proposed modification protocols allowed for tailoring electrochemically active surface area and electron transfer kinetics determined by electrochemical techniques (CV, EIS) with [Fe(CN)6]4-/3- redox probe. The X-ray photon spectroscopy and SEM imaging were applied to determine the delivered surface chemistry. The CB-PLA hydrolysis in alkaline conditions and under anodic polarization greatly impacts the charge transfer kinetics. The enzymatic hydrolysis of PLA with proteinase K has led to highly efficient results yet requiring an unsatisfactory prolonged activation duration of 72 h, efficiently reduced by the electrolysis carried out in the presence of the enzyme. Our studies hint that the activation protocol originates from surface electropolymerization rather than synergistic interaction between electrolysis and enzymatic hydrolysis. The detailed mechanism of CB-PLA hydrolysis supported by electrolysis has been elaborated since it pawed a new route towards a time-efficient and environmentally-friendly activation procedure.