(311b) Electrospinning of End-Capped Oligopeptides

Conductive nanofibers mats are used for sensors, electrically conductive membranes, wearable textiles, biomedical devices, and many other applications. To fabricate conductive fibers, generally, a conductive filler such as carbon nanotubes (CNTs) or metal nanowires is mixed with a polymer solution that is extruded into the fiber form. Unfortunately, both the CNTs and metal nanowires are much stiffer than the polymer matrix and this mechanical mismatch causes the composite fibers to fall apart upon stretching. While conductive polymers are flexible in nature, they suffer from limited solubility. Therefore, a novel approach to synthesizing flexible, stretchable, and durable fiber mats featuring a conductive material that is highly soluble and easy to process is needed. In this presentation, we employed electrospinning to obtain conductive fiber mats featuring in-house synthesized conductive oligopeptides. We systematically evaluated the optimum peptide concentrations and electrospinning conditions needed to successfully electrospin pure peptide solutions (without any added polymers). Indeed, long and uniform fibers with an average fiber diameter of ~300 nm were obtained. We investigated the chemical stability of these fibers in aqueous solutions of various pH values. We also characterized the electrical properties of the fiber mats as a function of pH values, temperature, and relative humidity by employing chronoamperometry and voltammetry using a 2-point probe setup. Among these parameters, relative humidity has the most dominating effect as the conductivity increases by the four orders of magnitude when humidity increases from 30% to 90%. The electrical conductivity and mechanical properties of a single fiber were evaluated using atomic force microscopy (AFM). From our results, we suggest that pure peptide fibers have the potential to advance the next generation of wearable conductive fabrics.