Figure 2: Hydraulic actuation of hydrogel in water.
From: Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water
(a) Actuation time is defined as a ratio of actuation volume to supply rate. Actuation time versus supply rate from the pump for the unit-segment hydraulic hydrogel actuator in both experiments and finite element simulations. (b) Actuation force versus applied pressure for the unit-segment hydraulic hydrogel actuator in both experiments and finite element simulations. (c) Fast bending actuation of the hydraulic hydrogel actuator with actuation frequency around 1 Hz. The finite element simulation also captures the fully actuated state of the actuator and its maximum principal strain (middle inset image). (d) Slow swelling-driven osmotic actuation of a bulk PAAm-alginate hydrogel assembled with a Sylgard 184 layer. (e) Comparison of the actuation forces and frequencies between the hydraulic hydrogel actuators in this study and typical osmotic hydrogel actuators and muscle-powered bioactuators11,12,13,14,15,16,19,20,21,37,38,39. Note that the hydrogel actuators in a–d are dyed with colour for better visual representation. Scale bars, 1 cm (c,d).
