A dynamic surface pattern with a topography and fluorescence in response to environmental stimulus can enable information recording, hiding, and reading. Such patterns are therefore widely used in information security and anticounterfeiting. Here, we demonstrate a dynamic dual pattern using a supramolecular network comprising a copolymer containing pyridine (P4VP-nBA-S) and hydroxyl distyrylpyridine (DSP-OH) as the skin layer for bilayer wrinkling systems, in which both the wrinkle morphology and fluorescence color can be simultaneously regulated by visible light-triggered isomerization of DSP-OH, or acids. Acid-induced protonation of pyridines can dynamically regulate the cross-linking of the skin layer through hydrogen bonding, and the fluorescence of DSP-OH. On selective irradiation with 450 nm visible light or acid treatment, the resulting hierarchical patterned surface becomes smooth and wrinkled reversibly, and simultaneously its fluorescence changes dynamically from blue to orange-red. The smart surfaces with dynamic hierarchical wrinkles and fluorescence can find potential application in anticounterfeiting.
Dynamic micro-/nanowrinkle
patterns with response to multienvironmental
stimuli can offer a facile method for on-demand regulation of surface
properties, thus allowing for generation of a smart surface. Here
a practical yet robust strategy is described to fabricate redox, light
and thermal responsive wrinkle by building dynamic double interpenetrating
polymer network (IPN) as the top layer for a typical bilayer system.
IPNs were constructed through the photochemical reaction of a mixture
comprised of light-sensitive anthracene-containing polymer (PAN) and
redox-sensitive disulfide-containing diacrylate monomer (DSDA). Thanks
to the dynamic covalent reversible C–C bond in PAN and S–S
bond in DSDA, the morphology of wrinkled surface not only can be reversibly
and precisely (micrometer scale) tailored to all kinds of complicated
hierarchical pattern permanently, but also can be controlled temporarily
by irradiation of near-infrared light (NIR). A sine wave model is
proposed to investigate the dynamics of real-time reversible wrinkle evolution. This general approach based on IPN
allows independent multistimuli control over wettability and optical
properties on the wrinkled surface, thus, presents a considerable
alternative to implement a smart surface.
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