Figure 17.

(i) Shape-memory effect of photo-responsive polymer demonstrated by Lendlein et al. [13]. (A) grafted polymer film, (a) Permanent non-elongated shape, (b) temporary shape after mechanical elongation and irradiation with light >260 nm, the film stayed in the elongated state after removal of stress, (c) recovered shape, after irradiation with light <260 nm. (B) An interpenetrating polymer network film, (a) permanent shape, (b) temporary cork spiral shape, which results after irradiation from one side, (c) recovered shape after irradiation with UV light of wavelength <260 nm. Reprinted with permission from Macmillan Publishers Ltd [Nature] [13], copyright (2005).