Wet-Spun Porous Carbon\nMicrofibers for Enhanced Electrochemical\nDetection

Abstract

We present a novel copolymer-based, uniform porous carbon\nmicrofiber\n(PCMF) formed via wet-spinning for significantly improved electrochemical\ndetection. Carbon fiber (CF), fabricated from a polyacrylonitrile\n(PAN) precursor, is commonly used in batteries or for electrochemical\ndetection of neurochemicals due to its biplanar geometry and desirable\nedge plane sites with high surface free energy and defects for enhanced\nanalyte interactions. Recently, the presence of pores within carbon\nmaterials has presented interesting electrochemistry leading to detection\nimprovements; however, there is currently no method to uniformly create\npores on a carbon microfiber surface impacting a broad range of electrochemical\napplications. Here, we synthesized controllable porous carbon fibers\nfrom a spinning dope of the copolymers PAN and poly(methyl methacrylate)\n(PMMA) in dimethylformamide via wet spinning for the first time. PMMA\nserves as a sacrificial block introducing macropores of increased\nedge-plane character on the fiber. Methods were optimized to produce\nporous CFs at similar dimensions to traditional CF. We prove that\nan increase in porosity enhances the degree of disorder on the surface,\nresulting in significantly improved detection capabilities with fast-scan\ncyclic voltammetry. Local trapping of analytes at porous geometries\nenables electrochemical reversibility with improved sensitivity, linear\nrange of detection, and measurement temporal resolution. Overall,\nwe demonstrate the utility of a copolymer synthetic method for PCMF\nfabrication, providing a stable, controlled macroporous fiber framework\nwith enhanced edge plane character. This work will significantly advance\nfundamental investigations of how pores and edge plane sites influence\nelectrochemical detection.