fig4

Figure 4. GERs and GCRs as power sources. (A) GERs: a gas is produced by the chemical reaction of one or more reactants, increasing pressure when the reaction takes place in a sealed system. When a soft pneumatic actuator is attached to the system, the increase in pressure results in the actuation; (B) GCRs: a gas is used as a reactant for reaction with other chemical species, resulting in the decrease of pressure when the reaction takes place in a sealed system. When a soft pneumatic actuator is attached to the system, the decrease in pressure results in actuation. GERs: Gas evolution reactions; GCRs: gas consumption reactions.