Fig. 2

Autonomous thermo-mechanical oscillation, kinematic tracking, and mechanical analysis. a Photograph of TMES on a hot surface at 60 °C. b Infrared images and curvature change of TMES on the hot surface with different temperatures. c Fluorescent image of marked TMES in UV light and its 2D coordinate system. The inset is a photograph of marked TMES in visible light. d The 2D trajectory of marked points on the cross-section of TMES during a complete oscillation cycle from the leftmost to rightmost and then back to the leftmost position, at four different temperatures, 50, 55, 60, and 65 °C (from bottom to top). e Plot of center of gravity during a complete oscillation cycle based on trajectory of the marked points. f The 2D trajectory of center of gravity at different temperatures. g Time-dependent center of gravity in the x-axis during three consecutive oscillation cycles at different temperatures. All scale bars correspond to 1 cm