Fig. 4.
Spiral ribbons formed by the wide TNE films with the thickness 35.2 μm. (A) Shape of the L-geometry ribbons: left-handed at 374 K; right-handed at 336 K. The ribbon width is 0.76 mm. (B) Shape of the S-geometry ribbons: right-handed at 374 K; left-handed at 330 K. The ribbon width is 0.83 mm. (C) Temperature dependence of the inverses of the helical pitch (pH) and the diameter (d), where the lines represent the theoretical predictions. The pitches of the left- and right-handed twist are defined to be positive and negative, respectively. The inverse of the pitches is represented by the open symbols and the inverse of the diameters by the filled symbols. The (red) circles and (blue) squares represent, respectively, the data of the L-geometry and the data of the S-geometry. The thick (solid or dashed) lines represent the theoretical predictions for the structural parameters of spiral ribbons, and the thin dashed lines are the theoretic prediction of the pitch inverse of helicoids.