Characterization of linear-type actuators
The experimental setup is shown in Figure S3. The characterization was
conducted by applying a voltage of up to 1000 V with 100 V incremental
to the actuator. The voltage was supplied from a high-voltage DC-DC
converter (XP Power, CB101). The actuation strain as a function of the
applied voltage was then acquired by measuring the displacement of the
actuator tip, which was done by using a camera (Nikon, D3500) followed
by image processing.