Development of Shape Memory Alloy Based Micro-Tentacle Actuator Using Two-Photon Polymerization

In recent few decades, research on miniaturization of soft robotics expands to new applications that require delicate manipulation in small area, such as microsurgery and the study of small biological specimen. Various types of smart materials such as photo-sensitive polymers, ionic polymer metal composites, and magnetic soft composites are utilized for actuation mechanism of small-scale actuators. Shape memory alloy is one of the promising candidates for developing a small-scale actuator because the shape memory effect of this alloy is preserved in submicron area with high work density. In this research, a miniaturized smart soft composite actuator fabrication method is proposed. A 3D micro-scaffold structure is printed by using two-photon polymerization process and shape memory alloy wires are embedded in them to form a composite actuator. The morphing motion is achieved via local resistance heating of the carbon nanotube layer deposited inside the device and the direction of morphing is varied according to the direction of the scaffold lamination. The proposed device produces a force of 400 μN and can achieve a bending angle up to 80° approximately. Applications of the device are demonstrated by grabbing small and delicate objects.