Fig. 1.

Schematic illustration and working principle of the triboelectric micromotor. a Schematic diagram of the TM and SEM image of the PTFE film. b Image of the rotating micromotor. c Working process of the micromotor during a quarter of cycle by the Coulomb forces of accumulated charges. d Diagrammatic sketch of the rotating angle, tilt angle and included angle. e Simulated curves between rotor torque and rotation angles during a quarter of cycle clockwise and anticlockwise with four blades and included angle of 180 degrees