Rewritable acidochromic papers based on oxazolidine for anticounterfeiting and photosensing of polarity and pH of aqueous media

Abstract

Oxazolidine is a new category of stimuli-chromic organic compounds with unique characteristics in response to polarity, pH changes, water, light, and metal ions that were well-known as solvatochromism, acidochromism, hydrochromism, photochromism, and ionochromism, respectively. Therefore, oxazolidine derivatives have been developed for their potential applications in chemosensors, anticounterfeiting, and rewritable hydrochromic papers. In this study, various oxazolidine derivatives containing hydroxyl and naphthalene substituted groups were synthesized by using two different indolenine compounds. The synthesized oxazolidine derivatives were used for investigation of solvatochromism in different solvents, and also acidochromism in various pHs by using UV–Vis and fluorescence spectroscopies. In addition, the oxazolidine derivatives were coated on cellulosic papers using a layer-by-layer strategy to develop rewritable acidochromic papers for printing of security tags on cellulosic papers by using acidic and alkaline solutions as water-based inks. Therefore, the developed rewritable acidochromic papers could be used as security papers.

Dual-Color Photoluminescent Functionalized Nanoparticles for Static-Dynamic Anticounterfeiting and Encryption: First Collaboration of Spiropyran and Coumarin

“…In recent years, increasing the security of anticounterfeiting inks based on photoluminescent materials has been the most important challenge for researchers in this field, and a significant solution to overcome this challenge is the development of novel anticounterfeiting technology with multi-level security. A wide range of anticounterfeiting materials based on hydrochromic, photochromic, fluorescence, acidochromic, and mechanochromic materials were developed to design a single formulation of anticounterfeiting inks with complex security levels and multi-step authentication. ,− ,− To develop advanced anticounterfeiting inks with multi-level security, a new approach was used in the current work by mixing (in different ratios) fluorescent polymer nanoparticles that have cyan emission (under UV-light irradiation of 254 nm, named FPMCNPs-CUDOH) with photochromic polymer nanoparticles that have time-dependent red emission (under UV-light irradiation of 365 nm, named FPMCNPs-SPOH). For this purpose, the initial latex samples (FPMCNPs-1, FPMCNPs-4, and FPMCNPs-7) containing ester, hydroxyl, and amide functional groups were modified with 10 wt % (with respect to the solid polymer content) of CUDOH (as a cyan emissive organic dye) by the physical post-polymerization modification method.…”

Stimuli-Responsive Dendritic Macromolecules for Optical Detection of Metal Ions and Acidic Vapors by the Photoinduced Electron Transfer Mechanism: Paper-Based Indicator for Food Spoilage Sensing

“…The oxazolidine derivatives (OX 1 –OH, OX 2 –OH, OX 1 –Nitro, and OX 2 –Nitro) were also synthesized using the procedure reported by Sheng and co-workers (Supporting Information). − Chemical structures of OX 1 and OX 2 derivatives were characterized by 1 H NMR analysis (CDCl 3 as the solvent), and the results were reported in our previous studies. , …”

“…38−40 Chemical structures of OX 1 and OX 2 derivatives were characterized by 1 H NMR analysis (CDCl 3 as the solvent), and the results were reported in our previous studies. 41,42 2.3. Synthesis of SP-PAMAM Dendrimers.…”

Development of pH sensing colloidal nanoparticles and oil/water separating electrospun membranes containing oxazolidine from functional polymers

“…Characterization of the chemical structure of the oxazolidine derivative was done by 1 H NMR analysis (D 2 O as the solvent), and the corresponding spectra were shown in our previous works. 55,56…”

“…Physical incorporation of these materials resulted in some optical properties, such as photoresponsivity, high resolution, and erasable/ rewritable capability of the fluorescent nanoparticles. [53][54][55][56] Photoluminescent nanoparticles and nanofibers with applications in pH-responsive chemical sensors and oil/water separation, respectively, have not comprehensively been studied. However, some studies have been investigated in the field of nanofibers as membranes for oil and water separation.…”