Reversible Colorimetric Sensor for Moisture Detection in Organic Solvents and Application in Inkless Writing

Abstract

Colorimetric sensors based on Sudan-III (1) and Alizarin red S (2) have been developed for the detection of a trace amount of water in organic solvents such as THF, acetone, acetonitrile, and DMSO. The deprotonated (anionic) forms of 1 and 2 namely 1.F and 2.F are reprotonated by using a trace amount of water. Deprotonation of 1 and 2 was obtained by using fluoride anion. Test papers of 1.F and 2.F in organic solvents with and without moisture showed dramatic changes in color. Receptor 1.F exhibits high sensitivity for water in acetone and THF with the detection limit as low as 0.0042 and 0.0058 wt %. Remarkably, probes 1.F and 2.F are reversible in nature both in solution and in test strips. 1.F and 2.F are reversible and reusable for sensing moisture in the organic solvents with high selectivity, high sensitivity, and fast response. The reversible moisture sensor 1.F has also been used for application in inkless writing.

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.…”

Development of an intramolecular charge transfer-type colorimetric and fluorescence sensor for water by fusion with a juloidine structure and complexation with boron trifluoride

“…Several strategies have been demonstrated to meet the requirement, such as intramolecular charge transfer (ICT), [5][6][7][8][9] excited state intramolecular proton transfer (ESIPT), [9][10][11] photo-induced electron transfer (PET), [12][13][14][15][16][17][18] aggregation-induced emission (AIE), 7,29,30 decoloration of hydrogen-bonding photochromic dyes, 31 and other water-triggered mechanisms. [19][20][21][22][23][24][25][26][27][28] Generally, in each system, there is a specic range of water concentration available for detection; AIE is observed in high water concentrations, 7,29,30 whereas other systems exhibit optical changes in a relatively low concentration range. In this context, a reasonable approach to incorporating two mechanisms into one sensor molecule has been developed to detect and determine water in organic solvent sensitively in a wide concentration range, including the combinations of ICT or PET and AIE, [32][33][34][35][36][37][38][39] two water-induced reactions, 40 and two ICT-related mechanisms, 41,…”

The Colorimetric Signaling of Water Content by a Deprotonated Schiff Base in some Aprotic Organic Solvents

“…Recently, Kumar et al . utilized dye‐fluoride complex for the colorimetric detection of water in THF (LOD=0.0058 wt % ) and acetone (LOD=0.0042 wt %) through protonation and deprotonation . The same research group also reported dye‐fluoride complex for water signalling in acetonitrile (LOD=0.0011 wt %) and THF (LOD=0.0026 wt %) .…”