Inkjet-Printable Hydrochromic Paper for Encrypting Information and Anticounterfeiting

Abstract

Developing rewritable papers has gathered immense interest in recent times in view of developing sustainability in print media without exhausting environmental resources. We herein present a rapid and facile procedure for the fabrication of a communication medium by treating the surface of a paper with synthetic organic molecules, after which plain water could be used as an ink to print and reprint numerous times on the treated paper before disposal. Interestingly, as the paper comes in contact with water, the molecules are driven to reorganize in a slip-stacked arrangement. This alters their ground and excited state properties by hydrogen-bond-assisted nonradiative decay, in which the associated changes are visible to the naked eye. The changes evolved are sensitive to the solubility parameter of the solvent and thermally reversible, thus linking the hydrochromic property to the paper. Against a background of concerns over a rise in counterfeiting and leaks of confidential information, prospects for encrypted communications and anticounterfeiting is herein demonstrated.

Hydrochromic CsPbBr3 Nanocrystals for Anti‐Counterfeiting

“…Depending on the stimuli source,s mart luminescent materials can be divided into different categories, such as mechanochromic, [5,6] thermochromic, [7,8] vapochromic, [9,10] photochromic, [11][12][13] hydrochromic ones. [14][15][16] Among various smart materials,h ydrochromic ones that are responsive to water or moisture have drawn special interest because of their characteristic advantages,s uch as low cost, simple operation and fast response. [17] As ar esult, they have been demonstrated to be widely used as humidity sensor,water-jetbased rewritable printing on paper,a nd anti-counterfeiting material.…”

Luminescence anti‐counterfeiting: From elementary to advanced

“…The anti‐counterfeiting labels in multilevel luminescence anti‐counterfeiting can change more than two times under the regulation of excitation light, luminescence lifetime, heat stimuli, chemical reagents, mechanical force, and so on. Based on the category of regulation factors, multilevel luminescence anti‐counterfeiting can be divided into five types: (1) regulated by excitation light; [ 64–80 ] (2) co‐regulated by excitation light and luminescence lifetime; [ 81–92 ] (3) co‐regulated by excitation light and heat stimuli; [ 35,63,93–96 ] (4) co‐regulated by excitation light and chemical reagents; [ 16,97–105 ] and (5) co‐regulated by other factors. [ 106–121 ]…”

“…Similarly with other chemical reagents, water, a kind of common, safe, and nontoxic chemical reagent, can also regulate the luminescence of anti‐counterfeiting label. [ 100,102,103,105 ] Recently, Yang et al. [ 103 ] prepared CDs with the property of aggregation‐induced emission (AIE) via one‐pot solvothermal treatment, and painted an anti‐counterfeiting label by employing hydrophobic CDs (H‐CD) solution as ink (Figure 7D).…”

Hydro‐Assisted Self‐Regenerating BrominatedN‐Alkylated Thiophene Diketopyrrolopyrrole Dye Nanofibers—A Sustainable Synthesis Route for Renewable Air Filter Materials

“…The increase in bundle diameter after regeneration may be attributed to the effect of the dissolved PM content in the precursor solution. [ 57 ]…”