Chemically Polymerized Polypyrrole on Glucose-Porcine Skin Gelatin Nanofiber as Multifunctional Electrochemical Actuator-Sensor-Capacitor

Multifunctional materials requiring low functional voltages are the main goal of new industrial smart technologies. Polypyrrole (PPy) was chemically synthesized by a simple dip-coating process on glucose-porcine skin gelatin nanofibers, accelerating mass production, here shown on nanofiber scaffolds (NFs) with those consisting of composites. The isometric and isotonic characterizations by electro-chemo-mechanical deformation (ECMD) of NFS-PPy are obtained from cyclic voltammetric and chronoamperometric responses in lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium triflouromethanesulfonate (LiTF) and sodium perchlorate (NaClO₄) in propylene carbonate (PC). The results indicate a prevalent anion-driven actuation of the linear actuator (expansion by oxidation and contraction by reduction). Different stress (4-2 kPa) and strain (0.7-0.4%) gradients are a function of the anion Van der Waals volume. During reversible actuation (expansion/contraction), the material stores/releases energy, obtaining greater specific capacitance, 68 F g^-1, in LiTFSI solutions, keeping 82% of this capacity after 2000 cycles. The sensitivity (the slope of the linear sensing equation) is a characteristic of the exchanged anion. The reaction of the PPy-coated nanofiber is multifunctional, developing simultaneous actuation, sensing, and energy storage. The materials were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy.