Programmable light-driven swimming actuators via wavelength signal switching

Abstract

Light-driven swimming actuators with different motion modes could lead to many previously unachievable applications. However, controllable navigation often requires focusing light precisely on certain positions of the actuator, which is unfavorable for accurate dynamical operation or in microscale applications. Here, we present a type of programmable swimming actuators that can execute wavelength-dependent multidirectional motions via the Marangoni effect. Several multi-degree of freedom swimming motions have been realized: Forward-and-backward and zigzag actuators can execute one-dimensional (1D) and 2D linear motion, respectively; bidirectional gear rotation as angular motion can be regulated to obtain tunable speeds; and the turning actuator as a "freighter" is able to turn left, right, and go straight for precise maze navigation. A mechanical measurement system is established to quantitatively measure the driving force of the motion directly. The accessible wavelength-selective strategy presented here can inspire further explorations of simple and practical light-driven materials and systems.

Aligned Magnetic Nanocomposites for Modularized and Recyclable Soft Microrobots

“…The past decade has witnessed the rapid growth and thriving development of soft robotics, − from the design, , fabrication, , and control, , to the promising application in diverse engineering fields including biomedical diagnosis and surgery, , subterrane, space and deep-sea exploration, search-and-rescue in hazardous environments, , object manipulations at different length scales, ,− among many others. ,− Miniature soft robots, with the size ranging from micrometers to millimeters, have attracted particular attention due to their capability of noninvasively accessing narrow and confined spaces, and thus possess high potential for medical and bioengineering applications. − Significant advances have been lately achieved in developing miniature soft robots, which are generally constructed by different types of smart materials and actuated via various external stimuli such as light, − heat, , chemicals, , humidity, , and acoustic and electromagnetic fields. ,,,,− By deliberately designing the structure and tuning the properties of the responsive materials inside the robots, heterogeneous and asymmetrical deformation can be generated in a programmed manner. Such deformation can be controlled spatiotemporally by applying proper time-varying stimuli and then induce desired locomotion of the robots upon interacting with the surroundings (either terrestrial, aquatic, or aerial).…”

Optically Triggered Nanoscale Plasmonic Dynamite

“…Actuation and propulsion by light is a convenient way to manipulate nano-objects/micro-objects with remote controllability, which are mostly based on optical forces and photothermal-induced forces, − but again their force output is small (∼pN) and speed is slow, which strongly restrict their performances to liquid environment or semiliquid interface . Although laser-induced metal jetting and ablation can be used for forward transfer of nanoparticles in an efficient and controllable manner in dried state, in-plane manipulation and generality of this technique are still limited .…”

Thermally Driven Self-Rotation of a Hollow Torus Motor

“…In recent years, based on various stimuli-responsive materials including thermally responsive polymer materials [ 26 , 27 ], liquid crystal elastomers (LCEs) [ 28 , 29 , 30 , 31 ], dielectric elastomer [ 32 , 33 , 34 , 35 ], hydrogels [ 36 , 37 ], and ion gels [ 38 , 39 ], a wealth of self-excited motion modes have been proposed, such as rolling [ 40 , 41 ], vibration [ 24 , 31 , 40 , 41 ], torsion [ 41 , 42 ], stretching and shrinking [ 10 , 40 , 43 ], swinging [ 44 ], buckling [ 45 , 46 ], jumping [ 47 , 48 , 49 ], rotation [ 25 , 28 ], eversion or inversion [ 27 , 50 ], expansion and contraction [ 51 , 52 ], swimming [ 53 ] and even group behavior of several coupled self-excited oscillators [ 54 ]. The self-oscillating system is usually accompanied with damping dissipation, and its motion is a non-equilibrium dissipation process.…”