Light-driven continuous rotating Möbius strip actuators

Abstract

Twisted toroidal ribbons such as the one-sided Möbius strip have inspired scientists, engineers and artists for many centuries. A physical Möbius strip exhibits interesting mechanical properties deriving from a tendency to redistribute the torsional strain away from the twist region. This leads to the interesting possibility of building topological actuators with continuous deformations. Here we report on a series of corresponding bi-layered stripe actuators using a photothermally responsive liquid crystal elastomer as the fundamental polymeric material. Employing a special procedure, even Möbius strips with an odd number of twists can be fabricated exhibiting a seamless homeotropic and homogeneous morphology. Imposing a suitable contraction gradient under near-infrared light irradiation, these ribbons can realize continuous anticlockwise/clockwise in-situ rotation. Our work could pave the way for developing actuators and shape morphing materials that need not rely on switching between distinct states.

Light‐Fueled Polymer Film Capable of Directional Crawling, Friction‐Controlled Climbing, and Self‐Sustained Motion on a Human Hair

“…Such strategy can be realized using a self‐oscillation process, in which the actuator sustains periodic motion upon a non‐periodic external stimulus through a built‐in negative feedback mechanism. [ 42 , 43 , 44 , 45 ] Several pioneering examples have shed light on this direction, such as a wave‐like walker, [ 37 ] rolling rod for mass transport and weightlifting, and continuous rotating Möbius ring, [ 46 , 47 , 48 ] all serving as primary examples for a truly autonomous robot without human interference. Along this line, the following demonstration of self‐walking on a human hair presents an untethered robot capable of an elementary form of autonomy.…”

Light-modulated liquid crystal elastomer actuator with multimodal shape morphing and multifunction

“…For most developing LCE actuators and shape-morphing materials, those functions mentioned above could not be achieved in a single actuator. 48,49…”

Not another computer algebra system: Highlighting wxMaxima in calculus

“…All Möbius bands have a twofold symmetry rotational axis, for which a 180 • rotation results in strips indistinguishable from the original. The surface finds abundant applications in physical sciences, including nanostructures [16], metamaterials [17], polymeric materials [18], and photonic crystals [19].…”