Biodegradable Electrohydraulic Soft Actuators

Abstract

Biodegradable materials decompose and return to nature. This functionality can be applied to derive robotic systems that are environmentally friendly. This study presents a fully biodegradable soft actuator, which is one of the key elements in “green” soft robotics. The working of the actuator is based on an electrohydraulic principle, which is similar to that of hydraulically amplified self‐healing electrostatic actuators. The actuator developed in this study consists of a dielectric film made of polylactic acid (PLA) and polybutylene adipate‐co‐terephthalate (PBAT), with soybean oil as the dielectric liquid and electrodes made from a mixture of gelatin, glycerol, and sodium chloride (NaCl). The synthesized biodegradable electrode material exhibits a Young's modulus of 0.06 MPa and resistivity of 258 Ω·m when the mass fraction of NaCl relative to the amount of gelatin and glycerol is 10 wt%. The softness and resistivity of the electrode material results in actuation strain values of 3.2% (at 1 kV, corresponding to 1.2 kV mm−1) and 18.6% (at 10 kV, corresponding to 9.6 kV mm−1) for the linear‐type and circular‐type actuators, respectively. These values obtained for the biodegradable electrohydraulic soft actuators are comparable to those of nonbiodegradable actuators of the same type, representing the successful implementation of the concept.

Sustainable Robots 4D Printing

“…Notably, PLA has been used the most in the manufacture of BSSA. Numerous authors have reported that this material can be used as an SMP in thermal, [61,71,73,81,82,116,119,120,[123][124][125][126][127][128]132,133,196] electrothermal, [109] electrochemical, [135] magnetic, [69,75,78,82,197] and electrohydraulicbased [102,121] actuating soft systems. Several research groups have recently strengthened 3D-printed polymers by incorporating continuous fibers.…”

“…No-tably, from a material point of view, PLA has been employed the most in the fabrication of biodegradable soft actuators. Many authors have reported the applicability of this material as a SMP in thermal, [61,71,73,81,82,116,119,120,[123][124][125][126][127][128]132,133,197] electrothermal, [109] electrochemical, [135] magnetic, [69,75,78,82,197] and electrohydraulicbased [102,121] actuating soft systems.…”

“…Regarding their applicability, biodegradable 3D/4D printed soft actuators are utilized in many fields, such as agriculture, [ 60 ] biomedicine, [ 61–93 ] micro positioning, [ 67,79,94–97 ] smart surgical instruments, [ 64,98–101 ] soft rehabilitation devices, [ 98,102,103 ] drug delivery microswimmers, [ 64,67,68,70,72,73,77,84,85,88,94,34,104–108 ] sustainable electronics devices, [ 109–111 ] soft smart fabrics, [ 64 ] muscle tissue membranes, [ 65,76,89,94,96,112,113 ] in‐vivo robotics, [ 67,74,83,86,89–91,93,99–101 ] wearable devices, [ 95,103,111,114–118 ] soft smart prosthetics, [ 114 ] bionic devices, [ 69,72,73,114 ] aeronautics, [ 119,120 ] health monitoring equipment, [ 111,118 ] edible robots, [ 121 ] biomimetic scaffolds, [ 30,62,76,97,115,122,123 ] environmental monitoring equipment, […”