Photoluminescent Polymer Nanoparticles Based on Oxazolidine Derivatives for Authentication and Security Marking of Confidential Notes

Abstract

Colloidal materials have widely been used to develop innovative anticounterfeiting nanoinks for information encryption. Latex nanoparticles based on methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) bearing hydroxyl functional groups were synthesized via semicontinuous miniemulsion polymerization. The size determination of the nanoparticles and microscopic results showed mostly spherical nanoparticles with a narrow size distribution and a mean size of about 80 nm. Two oxazolidine derivatives were physically doped at the surface of the nanoparticles to prepare photoluminescent polymer nanoparticles. Hydroxyl functional groups at the surface of the nanoparticles led to their hydrogen bonding interactions with the doped luminescent compounds. Optical analysis of the photoluminescent nanoparticles displayed different fluorescence emission and UV−vis absorbance intensities based on the amount of polar groups located at the surface of colloidal nanoparticles. Reducing the particle size to below 100 nm along with increasing the surface area can assist the decrease of the light reflectance and improvement of the latex nanoparticles' efficiency in the anticounterfeiting industry. This preparation methodology can efficiently provide remarkable photoreversible anticounterfeiting nanoinks used in different applications, such as print marking, security encoded tags, labeling, probing, and handwriting.

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

“…Polarity of the polymer matrix can significantly affect optical properties of oxazolidine. 2,15,56,69,83,84 This indicates that the polymeric nanoparticles containing oxazolidine molecules are noteworthy candidates of chemosensor applications.…”

Synthesis and Application of Fluorescent Polymer Micro‐ and Nanoparticles

“…also prepared photoluminescent polymer particles containing oxazolidine molecules, which were used as anticounterfeiting nanoinks. [ 117 ]…”

“…Recently, Alidaei-Sharif et al also prepared photoluminescent polymer particles containing oxazolidine molecules, which were used as anticounterfeiting nanoinks. [117] As mentioned above, particles with a range of functional groups on the surface have been synthesized. However, it was found that the increased concentration of amide groups on the particle surface could lead to particle destabilization, which was not conducive to achieving the stability of chromophores with maximum concentration on the particle surface.…”

Thermal-Induced Chromism and Fluorescence Emission of Rhodamine B-Containing Polymers with Different Polarities: Tracking Temperature and Development of Thermochromic Labels

“…Rhodamine B derivatives, , fluorans, − spiropyrans, − and crystal violet lactone are some important examples of leuco dye compounds that are generally used in the preparation of thermochromic materials. , Thermochromism is classified into reversible and irreversible categories, where the reversible systems have gained more attention because of their extensive applications based on temperature fluctuations during the day and in different seasons, such as in the military, construction, anticounterfeiting, sensors, etc . For the reversible coloration–decoloration of organic leuco dyes, a three-component system including leuco dye, solvent, and developer is required. , Color developers play the role of chroma, and are often from the category of phenolics (a weak acid such as Bisphenol A), aromatic amines, lauryl gallate, ethyl gallate, carboxylic acids, and Lewis acids that are usually used for the solid state of the thermochromic materials. ,− Strong proton donors, such as hydrochloric acid, are suitable for both liquid and solid states, and they provide a proton to the color former. A suitable balance is vital between the acidity of the color developer and basicity of the leuco dye .…”

“…For the reversible coloration− decoloration of organic leuco dyes, a three-component system including leuco dye, solvent, and developer is required. 22,23 Color developers play the role of chroma, and are often from the category of phenolics (a weak acid such as Bisphenol A), aromatic amines, lauryl gallate, ethyl gallate, carboxylic acids, and Lewis acids that are usually used for the solid state of the thermochromic materials. 14,24−26 Strong proton donors, such as hydrochloric acid, are suitable for both liquid and solid states, and they provide a proton to the color former.…”