Figure 6.

Application of the AAP‐photoswitch with tunable half‐lives to write transient information patterns in solid state polymer films. (a) Scheme of the AAP‐Polymer and CNC which are both equipped with sulfonic acid moieties. (b) Linearized Eyring plots determining the Gibbs energy (ΔG ^≠=109.8±1.4 kJ mol⁻¹) and the half‐life [τ _1/2 (25 °C)=21.9±0.5 d] of AAP attached to the polymer (black squares) compared to free PEG‐AAP in solution (blue circles). (c) Photopatterning of CNC/AAP‐Polymer films via irradiation through an inkjet‐printed photomask with a UV lamp (370 nm) for 3 min. (d,h) Homogenous films before UV irradiation. (e,i) After UV irradiation, both films clearly illustrate the pattern of the exposed areas. (f,j) While the pattern is clearly visible after 24 h in case of films cast from pH 7.4 (j), it is strongly faded already in the same time for films cast from pH 4.0 (f). (g,k) After 72 h, the pattern is not visible anymore at pH 4.0 (g), because most Z‐AAP is converted back into E‐AAP. In contrast, the film cast from pH 7.4 clearly illustrates the pattern after 72 h in the dark (k).