Fig. 4. Surface temperature effects on the active self-turning behavior of the twisted, helical, and hybrid ribbons.

(A) The trajectories of the twisted (solid curves) and the helical (dashed curves) ribbons at different surface temperatures. (B) The trajectories of the hybrid ribbons before (solid curves) and after flipping (dashed curves) at different surface temperatures. (C) The turning radius as a function of surface temperatures for all the ribbons. (D) The diameter change of the two twisted and helical ends in the hybrid ribbon with surface temperatures. Inset shows the schematic of a conical-like shape in the hybrid ribbon with different diameters on two ends for active turning.