Surface molding of multi-stimuli-responsive microgel actuators

The fabrication of soft hydrogel actuators that rapidly respond to multiple stimuli in ambient environments is a challenge. This article describes a method-based on surface molding-to generate multi-stimuli-responsive soft actuators consisting of arrays of geometrically patterned hydrogels on elastomeric supports. The stimuli-responsive properties of these actuators were derived from functional fillers that were added directly to the prepolymer or synthesized within the gels using simple reactions. These actuators respond rapidly and can be rationally controlled by a variety of stimuli, including humidity, magnetic fields, or light, depending on the filler type. The reported fabrication strategies will be useful to the design and production of "programmable" soft actuator systems useful to, for example, soft robotics.