Carbon-nanofiber-based nanocomposite membrane as a highly stable solid-state junction for reference electrodes

There is currently a need for a reliable solid-state reference electrode, especially in applications such as autonomous sensing or long-term environmental monitoring. We present here for the first time a novel solid-state nanofiber junction reference electrode (NFJRE) incorporating a junction consisting of poly(methyl methacrylate) and carbon graphene stacked nanofibers. The NFJRE operates by using the membrane polymer junction, which has a very high glass transition temperature (T(g)) and small diffusion coefficient, to control the diffusion of ions, and the carbon nanofibers lower the junction resistance and act as ion-to-electron transducers. The fabrication of the NFJRE is detailed, and its behavior is characterized in terms of its impedance, stability, and behavior in comparison with traditional reference electrodes. The NFJRE showed a response of <5-13 mV toward a variety of electrolyte solutions from 10(-5) to 10(-2) M, <10 mV over a pH range of 2-12, and excellent behavior when used with voltammetric methods.