Inkjet printing of electroactive polymer actuators on polymer substrates

Abstract

Electroactive polymers (EAP) are promising materials for actuators in different application areas. This paper reports inkjet printing as a versatile tool for manufacturing EAP actuators. Drop-on-demand inkjet printing can be used for additive deposition of functional materials onto substrates. Cantilever bending actuators with lateral dimensions in the mm range are described here. A commercially available solution of electroactive polymers is dispensed onto metalized polycarbonate substrates using inkjet printing. These polymers exhibit piezoelectric behavior. Multiple layers are printed resulting in a film thickness of 5 to 10 μm. After printing, the polymer layers are annealed thermally at 130 °C. Top electrodes are deposited onto the EAP layer by inkjet printing a silver nanoparticle ink. The as-printed silver layers are sintered using an argon plasma - a recently developed sintering technique that is compatible with low TG polymer foils. After printing the EAP layers are poled. When applying an electric field across the polymer layer, piezoelectric strain in the EAP leads to a bending deflection of the structures. With driving voltages of 200 V the actuators generate displacements of 20 μm and blocking forces of approximately 3 mN. The first resonance frequency occurs at 230 Hz.