Resistance Temperature Detectors Fabricated via Dual Fused Deposition Modeling of Polylactic Acid and Polylactic Acid/Carbon Black Composites

Handling electric connections in 3D-printed electrodes and sensors

Voltammetric and amperometric sensors typically consist of an electroactive surface, an electrode substrate, and connection tracks. While metal connectors exhibit negligible resistance, semiconductor materials, conductive polymers, or composites can introduce significant electrical resistance. This study investigates the electrical behavior of 3D-printed conductive polymer tracks and metal connections, focusing on limitations and improvements. Carbon black PLA (CB-PLA) was chosen for its favorable electrical properties. Printed tracks showed higher resistivity (17 Ω·cm) than the raw filament (6 Ω·cm). The electrical contact resistance (ECR) between nickel-plated metals and CB-PLA ranged from 102 to 103 Ω. Pressed contacts (e.g., alligator clips) were unstable and introduced noise, while a welded metal-polymer contact (WMPC), achieved via induction heating, improved stability. Despite high resistivity, the electrochemical behavior remained unaffected, apart from an Ohmic drop requiring compensation for accurate sensor performance. To address this, a four-electrode potentiostat was proposed for dynamic Ohmic drop compensation. Cyclic voltammetry experiments were performed using a custom 3D-printed electrode with dual conducting tracks to independently monitor potential and current. Results from a commercial four-electrode potentiostat were compared with those from a conventional three-electrode system. A four-electrode potentiostatic module (FEPM) was developed for compatibility with standard three-electrode instruments, yielding comparable results. Peak current varied linearly with hexaammineruthenium(III) concentration (R2 = 0.992) and with the square root of the scan rate (R2 ≥ 0.993). Differential pulse voltammetry confirmed enhanced performance with the four-electrode setup. These findings highlight key considerations for integrating 3D-printed components into electrochemical systems and mitigating ECR and Ohmic drop.

Advances in Monte Carlo Method for Simulating the Electrical Percolation Behavior of Conductive Polymer Composites with a Carbon-Based Filling

Conductive polymer composites (CPCs) filled with carbon-based materials are widely used in the fields of antistatic, electromagnetic interference shielding, and wearable electronic devices. The conductivity of CPCs with a carbon-based filling is reflected by their electrical percolation behavior and is the focus of research in this field. Compared to experimental methods, Monte Carlo simulations can predict the conductivity and analyze the factors affecting the conductivity from a microscopic perspective, which greatly reduces the number of experiments and provides a basis for structural design of conductive polymers. This review focuses on Monte Carlo models of CPCs with a carbon-based filling. First, the theoretical basis of the model's construction is introduced, and a Monte Carlo simulation of the electrical percolation behaviors of spherical-, rod-, disk-, and hybridfilled polymers and the analysis of the factors influencing the electrical percolation behavior from a microscopic point of view are summarized. In addition, the paper summarizes the progress of polymer piezoresistive models and polymer foaming structure models that are more relevant to practical applications; finally, we discuss the shortcomings and future research trends of existing Monte Carlo models of CPCs with carbon-based fillings.