Electrospun (K,Na)NbO₃ Piezoceramic Fibers for Self-Powered Tactile Sensing Application

This study investigates the electrical properties of electrospun ceramic fiber mats based on potassium sodium niobate ((K,Na)NbO3;KNN) for potential applications in soft-robotic tactile sensors. The rheological studies of electrospinning solutions exhibit shear thinning behavior, with a viscosity plateau between shear rates of 1-100 s(-1). The thermal decomposition behavior of the KNN samples is analyzed using thermogravimetric analysis; the samples show multistep decomposition processes leading into a phase pure perovskite structure. For the electrospun KNN fiber mats, the electrical characterization reveals ferroelectric hysteresis loops with a high leakage current of approximate to 270 nA at 20 kV cm(-1) and switching current behavior. The ferroelectric results indicate that a full polarization of KNN-fiber mats is not possible due to their electrical breakdown at high electrical fields. The integration of KNN short fibers into a soft-bending actuator demonstrates successful tactile sensing capabilities. The experimental findings reported here highlight the potential of electrospun KNN fiber mats for flexible and autonomous device applications in soft robotics.