Figure 4: Optically camouflaged hydrogel actuators and robots in water.
From: Hydraulic hydrogel actuators and robots optically and sonically camouflaged in water
(a) Transmittance in visible light range for the PAAm-alginate hydrogel, Ecoflex, Elastosil and Sylgard 184. (b,c) Images of the hydraulic fish-like actuators made of Ecoflex in mono-colour (b) and multi-colour (c) backgrounds. (d) Image of the fully actuated bending hydraulic hydrogel actuator in multi-colour background. (e,f) Images of the hydraulic fish-like actuators made of PAAm-alginate hydrogel in mono-colour (d) and multi-colour (e) backgrounds. Dotted lines are introduced in d–f to indicate the boundaries of transparent hydrogel structures in water. Scale bars, 1 cm (b–f).
