High‐Output Force Electrohydraulic Actuator Powered by Induced Interfacial Charges

Abstract

Herein, a novel soft actuator design is presented that simultaneously enables a high‐output force at a low operating voltage and an adjustable large normal displacement. The electrohydraulic actuator powered by induced interfacial charge (EPIC) uses the amplified electrostatic force when the surface charge‐inducing phenomenon of the polyvinyl chloride (PVC) gel and the geometrical gradient of the actuator are combined to reinforce the zipping motion of the liquid layer. This actuator produces a more than 50‐fold higher blocking force than conventional dielectric liquid‐coupled electrostatic actuators at 2 kV. This implies the possibility of expanding the applicability of soft actuators to high‐power transducers. This actuator is modeled as parallel capacitors by considering the interfacial‐induced charge; the ratio of the dielectric constant of the polymer film to that of the dielectric liquid is analyzed as the principal design criterion for optimizing the performance characteristics. The actuator prototype exerts a force as high as 16 times its body weight (25.5 g) and exhibits a large normal displacement of more than 20% of its height (8.5 mm). Furthermore, four actuators can lift a weight of 1.25 kg and one actuator can be used as a large‐aperture (diameter: 30 mm) varifocal lens (374% focal length variation).

A Superabsorbent Sodium Polyacrylate Printing Resin as Actuator Material in 4D Printing

“…The resulting force by this pressure is usually referred to as an actuator's blocking force. [36,52] To validate this force stroke relation, we recorded the swelling of 2 mm thick SAP 37/1 discs (radius of 5.6 mm) in water without and with an external load (100 kPa) over a time of 8 h. From the stress-strain curve in Figure 4a, a 100 kPa load is expected to decrease the relative elongation to 1.2 ± 0.2. Figure 4b shows the measured increase in thickness over time.…”

Stretchable, Transparent and Multifunctional PVC-gel Heater: A Novel Approach to Skin-Mountable, Wearable Thermal Devices.

“…It was reported that the deformation of PVC-gel is caused by electrostatic force acting on the anode due to the accumulated plasticizer as the charge carrier 44,45 . With these merits, PVC-gel was employed in soft actuators [46][47][48] , haptic interfaces 49 , tunable lenses 50 , soft sensors 51 , and electric generators 52 . It is newly suggested that PVC-gel can be applied in heaters due to its mechanical, optical, and thermal functionalities.…”

Flagellum‐Inspired Soft Rotary Motor

“…Over the past decade, substantial efforts have been made in the development of soft robots, which exhibit conformable complex motions that ensure safe interactions between humans and robots. [1][2][3][4] By employing various actuation methods, [5][6][7][8][9][10][11] soft robots are able to perform a variety of bioinspired deformations, [4,[12][13][14] ranging from bending, [15][16][17][18] contraction, [19][20][21] to elongation. [22][23][24] However, despite these advances, rotation remains a persistent challenge in soft robots.…”