Traditional (1D, 2D, and 3D) codes are widely used to provide convenient readouts of encoded information. However, manipulating and transforming the encoded information is typically difficult to achieve. Here, the preparation of three fluorescent (blue, green, and red) hydrogels containing both tetracationic receptor-anion recognition motifs and gel-specific fluorophores is reported, which may be used as building blocks to construct through physical adhesion fluorescent color 3D codes (Code A, Code B, and Code C) that may be read out by a smartphone. As a result, parts of the individual gel components that make up Code B can be replaced with other gel building blocks to form Code A via a cut and adhesion approach. A fluorophore responsive to ammonia is further incorporated into one of the hydrogels. This allows the gel block-derived pattern that makes up Code C to be converted to Code A by chemical means. Therefore, the encoded information produced by patterns of the present hydrogels may be transformed through either physical action or by exposure to a chemical stimulus. Due to the nature of the soft materials involved, the codes can be used as wearable materials.
Keywords: anion recognition; fluorescence; hydrogels; information; self-healing materials.
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