Water assisted biomimetic synergistic process and its application in water-jet rewritable paper

Abstract

The colour of water-jet rewritable paper (WJRP) is difficult to be expanded via single hydrochromic molecule, especially black. Here, inspired by the amazing phenomenon of bound-water in cells enabling various biological transformations via facilitating synergistic inter-/intra-molecular proton transfer, we present a simple strategy toward WJRP based on binary systems containing less-sensitive acidochromic dyes and mild proton donors (or developers). With such a binary system containing commercial black dye as the colouring agent, benzyl 4-hydroxybenzoate as the developer, and biomimetic bound-water as proton-transferring medium, we successfully achieve the long-awaited black WJRP. Printed images on such WJRP have excellent performances and long retaining time (>1 month). In addition, the robustness, durability and reversibility of WJRP could be increased distinctly by using polyethylene terephthalate as substrate. This strategy significantly expands hydrochromic colours to entire visible range in an eco-friendly way, which opens an avenue of smart materials for practical needs and industrialization.

Stimuli‐responsive photofunctional materials for green and security printing

“…98 To date, they have been successfully used for water-soluble color humidity sensors, [99][100][101][102][103][104][105][106][107][108] sweat hole mapping systems, [109][110][111][112][113] water detection in organic solvents, [114][115][116][117] and rewritable paper. 44,46,54,97,98,111,[118][119][120][121] Particularly, hydrochromic materials are very popular in the design of water-jet printing rewritable papers. This is because water is clean, low cost, convenient, and compatible with current inkjet printers.…”

“…The use of different acidic color-changing dyes can produce WJRP with different colors, including red, yellow, green, and blue. 54 A WJRP using two off-the-shelf dyes, namely Sudan-III and Alizarin Red S, has also been developed. It was used in colorimetric sensors to detect traces of water in organic solvents, such as tetrahydrofuran, acetone, acetonitrile, and dimethyl sulfoxide (DMSO).…”

“…Reproduced with permission. 54 Copyright 2018, Nature Publishing Group. C, Structure of the rewritable security paper and schematic diagram of the changes in the emission intensity before and after the addition of water.…”

Multi-color Reversible Photochromisms via Tunable Light-Dependent Responses

“…Smart materials that show reversible optical responses to different chemical and physical stimuli have led to the development of numerous optical devices finding wide applications as sensors, [1][2][3] security devices, 4,5 smart windows, 6,7 and information displays. [8][9][10][11] The stimuli sources including pH, 12 electricity, 13 temperature, 14 solvent, 15 mechanical deformation, 16 and light 17 show promise as external stimuli to control the response of the materials in both liquid and solid phases. Among the various stimuli applicable to induce reversible color-changing responses, light has become of particular interest because of the absence of direct contact with the sample, the possibility for long-distance control, and versatile control over the various properties of light such as wavelength, intensity, and time of irradiation.…”

Hydrophilic Doped Quantum Dots “Ink” and Their Inkjet‐Printed Patterns for Dual Mode Anticounterfeiting by Reversible Cation Exchange Mechanism

“…The application of QDs to next‐generation electronic and optoelectronic devices has transformed these industries . Based on the requirements of resolution, throughput, and defect tolerance, various patterning techniques can be considered, including photolithography, laser or electron beam (e‐beam) writing, self‐assembly, mask patterning, and inkjet printing . Among these, inkjet printing evolves as a method for the NCs and QDs patterning because of the high resolution, large areas, and low‐cost manufacturing .…”