Figure 4 : Photoresponsive actuator of αCD–Azo gel in water.

From: Expansion–contraction of photoresponsive artificial muscle regulated by host–guest interactions

Figure 4

(a) Experimental devices and the size of αCD–Azo gel(2, 2) in water. (b) Light irradiation from the left side of αCD–Azo gel(2, 2) for an hour. After ultraviolet irradiation, αCD–Azo gel(2, 2) bends to the right side. Subsequent irradiation with Vis light restores the initial state. (c) Light irradiation from the right side of αCD–Azo gel(2, 2) for an hour. After ultraviolet irradiation, αCD–Azo gel(2, 2) bends to the left side. Subsequent irradiation with Vis light restores the initial state. (d) Lateral view of αCD–Azo gel(2, 2) hung with a clip. Flexion angle (θ) is defined here. (e) Plots of irradiation time versus the flexion angle (θ) in αCD–Azo gel(2, 2). Blue and red areas denote ultraviolet irradiation and Vis irradiation, respectively. Blank area indicates dark storage without light irradiation. Flexion angle (θ) is measured using snapshots. (f) The repeated experiment of αCD–Azo gel(2, 2) irradiated with ultraviolet and Vis lights for 5 min. Plots show the correlation between irradiation time and flexion angle (θ). (g) Light irradiation from the left side of the ribbon-shaped αCD–Azo gel(1, 2) for 15 min. After ultraviolet irradiation, αCD–Azo gel(1, 2) forms a coil. Subsequent irradiation with Vis light restores the initial state. The colour profile of pictures under Vis light irradiation is adjusted to create clear images. The actual movie is shown in Supplementary Movie 8.