The Detachment Process and Release Efficiency of Polypyrrole/Gold Bilayer Actuators

Polypyrrole/gold (PPy/Au) bilayer actuators are used in a wide variety of applications, from microrobotics to drug delivery. In this paper, we demonstrate that the operation efficiency of PPy/Au bilayer actuators is influenced by the actuators´ geometry. During actuation, the outer edges of the actuators detached first and the subsequent release progressed toward the center of the actuators. Rectangular-, circular-, and trapezoidal-shaped actuators were fabricated, and for a given area, actuators with a larger perimeter exhibited faster release than actuators with a smaller perimeter. In addition to experimental work, finite-element analysis was performed to model the interfacial stress responsible for bilayer release. Insights gained in this paper besides PPy/Au actuators can be applied to other types of detachable actuators.