The microstructure of the SMPCs is temporarily deformed under external force, and the color disappears or changes simultaneously; after release of the external force, the SMPCs recover to the original shape and color. [15] Therefore, they have attracted tremendous interests in patterning, especially, in rewritable and reusable photonic crystal structural color materials. [16] For example, Fang et al. reported a pressure-and ethanol-responsive inverse opal SMPC, which is patternable and reconfigurable. [11,17] Wang et al. reported a thermoresponsive inverse opal SMPC that can be used for rewritable photonic papers with capabilities of multicolor writing and pattern copying. [18] Nonetheless, the fabrication of inverse opal PCs is usually time-consuming and costly. And the current researches mainly focus on the selection of SMPs and selection of external stimuli, [19] little researches involve new shape memory structural color materials with new structural colors.Recently, we reported a retroreflective structural color film (RSCF) derived from the mechanisms of retroreflection and thin-film interference combined with total internal reflection (TIR), [1b] and Goodling et al. reported a structural color within a droplet caused by the mechanisms of TIR and interference. [20] Based on the recently reported structural color mechanisms and method, herein, we further report a new kind of shape memory retroreflective structural color film (SMRSCF). This SMRSCF can not only be facilely fabricated on a large scale but also easily prepared in monochromatic, polychromatic, complex, and stitched patterns through customizing the templates. Moreover, the pattern templates are reusable, and the SMRSCFs are erasable and rewritable. This new kind of shape memory retroreflective structure color materials and their fabrication method we present here may find more promising applications than the previously reported SMPC materials. Results and Discussion Fabrication and Characterization of the SMRSCFThe fabrication process of SMRSCFs is schematically illustrated in Figure 1a. Briefly, the RSCF template was fabricated and used to prepare the polydimethylsiloxane (PDMS) template (Figure S1a, Supporting Information). The mixture of prepolymer A and curing agent B was poured onto the PDMS template to obtain the SMRSCF after cured and peeled off Almost all the shape memory structural color materials are based on the photonic crystal color mechanism, and there remain great challenges such as iridescent colors, hard fabrication, etc. Herein, a new kind of shape memory retroreflective structural color film (SMRSCF) is fabricated through the "two-template" method, based on the mechanisms of retroreflection and interference combined with total internal reflection. Different from photonic crystal color shape memory materials, this new SMRSCF displays brilliant monochromatic, polychromatic, complex, and stitched patterns, respectively, depending upon the flexibly customized templates. The shape memory polymers can further endow the film with exce...

While structural color materials are widely exploited in anti‐counterfeiting applications, it still remains a challenge to develop advanced and multifunctional structural colors for new anti‐counterfeiting technologies. Herein, a novel patterned retroreflective structural color film (PRSCF) with quadruple anti‐counterfeiting capacities is reported based on the changes in iridescent and non‐iridescent colors due to total internal reflection and interference mechanisms, reversible thermal‐responsive patterns owing to the shape memory effect, and reversible decryption and encryption of the patterns due to the surface wettability difference. This quadruple anti‐counterfeiting PRSCF greatly improves the security level and may find important potentials in precious artworks and displays.

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