Generation and characterization of flexible film integrated with microspring. (a) Schematic illustration of embedding microspring into a flexible polymer film. (b-d) Digital images of the embedding process and the fabricated flexible film. (e) Relative resistance change when stretching the films integrated with microsprings with different helical pitches. (f) Cycled stress-strain test of the composite. (g) Cycled tests of the relative resistance change of the films with microsprings with different helical pitches. The films were all stretched at double length.