P(VDF-TrFE-CTFE) Actuators with Inkjet Printed Electrodes

Abstract

Piezoelectric inkjet printing has proven its potential for use as an additive manufacturing technique for depositing thin films, and can be especially useful in the rapid prototyping of devices such as printed circuit boards (PCB), energy harvesters, capacitative sensors, or radio-frequency identification (RFID) antennae. The increasing availability of conductive inkjet inks of various compositions offer the means to print conductive patterns with relative ease in very little time. Whilst conductive inks are typically used to print conductive circuitry, the possibility of printing more modern and better performing smart materials opens the path for fully inkjet printed active devices. This offers the potential to manufacture smart materials and actuators faster, more economically, and with better repeatability than when using masking or photolithographic processes, without requiring specialized machinery or facilities. In this paper, we employ a low cost approach to manufacture 4 layer relaxor ferroelectric cantilever actuators using a commercial inkjet printer. A carbon black nanoparticle dispersion is printed onto an absorbent substrate to form a conductive bottom electrode, before a layer of P(VDF-TrFE-CTFE) is applied on top as the active material. Finally an additional layer of carbon black is printed on top of the polymer to form the top electrode. The finished actuators are poled to induce piezoelectric behavior in addition to the existing electrostrictive behavior. The resultant actuators can achieve deflections of up to 206 μm under loads of 300 V, and can achieve over 3 mm deflection when operating at resonance frequencies of 110-130 Hz.