Electrochemical actuation of free‑standing PEDOT : PSS/SU8 bilayer microactuators

Conjugated polymers are of great interest for micro‑actuators because, compared to large‑scale actuators, miniaturization improves their electrochemical properties by increasing speed, stress output etc. Recently, a novel fabrication process for obtaining robust large area free‑standing ultra-thin films made of the conjugated polymer poly (3, 4-ethylenedioxythiophene) doped with the polyanion poly(styrenesulfonate) (PEDOT:PSS) has been demonstrated. These nanofilms show a thickness ranging between few tenths to several hundredths of nm. This opens up the possibility of using such free‑standing PEDOT:PSS nanofilms to realize new all polymer electrochemical micro‑actuators using facile microfabrication methods. . Here, we report the processing methods and a validation of the micro-actuators’ working principle. Free standing PEDOT:PSS/SU8 bilayer micro‑actuators in the form of micro-fingers have been fabricated and patterned using a combination of standard microfabrication procedures. Reversible actuation of the PEDOT:PSS microactuators caused by electrochemical oxidation/reduction cycles was demonstrated and resulted in bending of the micro-fingers. Small, soft actuators may be useful for a number of applications, including microrobotics, microsurgery, and cell handling