Meniscus-Climbing System Inspired 3D Printed Fully Soft Robotics with Highly Flexible Three-Dimensional Locomotion at the Liquid-Air Interface.

Soft robotics locomotion at the liquid-air interface has become more and more important for an intelligent society. However, existing locomotion of soft robotics is limited to two dimensions. It remains a formidable challenge to realize three-dimensional locomotion (X, Y, and Z axes) at the liquid-air two-phase interface due to the unbalanced mechanical environment. Inspired by meniscus-climbing beetle larva Pyrrhalta, the mechanism of a three-phase (liquid-solid-air) contact line is here proposed to address the aforementioned challenge. A corresponding 3D printed fully soft robotics (named larvobot) based on photoresponsive liquid crystal elastomer/carbon nanotubes composites endowed repeatable programmable deformation and high degree-of-freedom locomotion. Three-dimensional locomotion at the liquid-air interface including twisting and rolling-up has been developed. The equation of motion is established by analyzing the mechanics along the solid-water surface of the larvobot. Meanwhile, ANSYS is used to calculate the stress distribution, which coincides with the speculation. Moreover, soft robotics is remotely driven by light in a precise spatiotemporal control, which provides a great advantage for applications. As an example, we demonstrate the controllable locomotion of the soft robotics inside closed tubes, which could be used for drug delivery and intelligent transportation.