Synergetic PEDOT degradation during a reactive ion etching process

Conjugated polymer etching is a key step in the integration of electro-chemical devices into microsystems, and one of the most important challenges for this type of material is to achieve fast etching with commercially available equipment. Conjugated polymer electrochemical devices are promising as they are used in different devices such as OLED, sensors, supercapacitors and actuators. The recent emergence of conducting interpenetrating polymer network actuators (IPN) based on poly(3,4-ethylenedioxythiophene) (PEDOT) has allowed operation frequencies of over 1 kHz to be attained, thus pushing the limits of the conjugated polymer technology. The plasma dry etching step of these PEDOT-based active mechanical devices, with high etching rates of around 2 μm min−1, enables the production of these electrochemomechanical devices. To understand the high etching rate of these materials a systematic study of the chemical degradation mechanism of each polymer has been carried on. From the analysis of the etching of all the polymer actuator components, a chemical self-degradation mechanism is proposed to explain the surprisingly high etching rate obtained for PEDOT based materials. Finally, to conclude this study, the usefulness of this fast etching is demonstrated with the operation of standalone micro-beam actuators.