Reconfigurable and Latchable Shape‐Morphing Dielectric Elastomers Based on Local Stiffness Modulation

Programmable soft materials exhibiting dynamically reconfigurable, reversible, fast, and latchable shape transformation are key for applications ranging from wearable tactile actuators to deployable soft robots. Multimorph soft actuator sheets with high load-bearing capacity are reported, capable of bending on multiple axis, made by combining a single dielectric elastomer actuator (DEA) with two layers of shape memory polymers (SMPs) fibers and an array of stretchable heaters. The rigidity of the SMP fibers can be reduced by two orders of magnitude by Joule heating, thus allowing the orientation and location of soft and hard regions to be dynamically defined by addressing the heaters. When the DEA is then actuated, it bends preferentially along the soft axis, enabling the device to morph into multiple distinct configurations. Cooling down the SMPs locks these shape changes into place. A tip deflection angle of over 300° at 5 kV is achieved with a blocking force of over 27 mN. Devices using two antagonistic DEAs are also reported that attain more complex shapes. Multimorphing is demonstrated by gripping objects with different shapes. An analytical model is developed to determine the design parameters that offers the best trade-off between large actuation and high holding forces.