Encryption and authentication of security patterns by ecofriendly multi-color photoluminescent inks containing oxazolidine-functionalized nanoparticles

Development of highly sensitive metal-ion chemosensor and key-lock anticounterfeiting technology based on oxazolidine

“…Compared to the other stimuli-chromic materials, chemical structure of the oxazolidine derivatives is very sensitive to characteristics of the surrounding media, where coloration and fluorescence emission could be significantly affected by the solute–solvent interactions. Therefore, the oxazolidine molecules are highly important candidates for colorimetric and fluorometric photosensing of different analytes especially metal ions 11 , 44 , 52 , 61 , 62 . Chemical structure and substituted functional groups on oxazolidine molecules are significant parameters on sensitivity and selectivity of metal ion chemosensors.…”

“…The oxazolidine derivatives were synthesized according to the literature 40 , 41 , 44 , 47 , 56 . A solution of 2-bromoethanol (25 mmol, 1.8 mL) and 2-buotanone (10 mL) was added dropwise to the solution of 2,3,3-trimethylindolenin (A, 20 mmol, 3.2 g) or 1,1,2-trimethylbenz[e]indole (B, 20 mmol, 2.1 g) and 2-buotanone (30 mL) at ambient conditions under reflux at 80 °C for 48 h to obtain reddish precipitates.…”

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

“…In addition, the environment polarity can affect intensity of fluorescence emission or coloration of these organic compounds, resulted from interactions between the polar functional groups with their conjugate structures. Related to this issue, the solvatochromism phenomenon in different solvents changes the colorimetric/fluorometric characteristics of conjugate organic structures by their interactions with different solvents and the corresponding variation of media polarity accompanied by hypsochromic (or blue) shift or bathochromic (or red) shift phenomena 19 – 25 . As a significant polarity parameter in aqueous solutions, variation of pH results in protonation or deprotonation of functional groups in the conjugated organic structures which act as aprotic or protic solvents, and their interactions are similar to the effect of electron-donating or electron-withdrawing groups.…”

“…A wide range of photochromic and fluorescent compounds has been used in the recent years for development of the colorimetric and fluorometric chemosensors by using solvatochromism, acidochromism, and ionochromism mechanisms 3 , 26 – 30 . Oxazolidine is a new category of conjugated organic chromophores with highly intense fluorescence emission and different colors depending on the functional substituted groups or chemical structure of the raw materials especially indolenine compounds 25 , 31 – 36 . Type of the substituted functional groups (electron withdrawing or electron donating) is the main effective factor to control fluorescence emission and coloration phenomena by formation of various interactions, such as polar-polar or hydrogen bonding, between oxazolidine with solvent molecules.…”

Security-Enhanced 3D Data Encryption Using a Degradable pH-Responsive Hydrogel

“…In recent years, functional materials have received great attention for their potential roles as promising security-strengthened data storage media [ 14 , 15 , 16 ]. Taking advantage of the unique reactivities of these functional materials, various data encryption platforms have been developed, including carbon dot composites [ 17 , 18 , 19 , 20 ], AIE Polymers [ 21 ], amorphous organic materials [ 22 ], oxazolidine-functionalized nanoparticles [ 23 ], tetraphenylethylene@graphene oxide [ 24 ], smart hydrogel materials [ 25 , 26 , 27 , 28 , 29 ], etc. Among these materials, hydrogel with unique three-dimensional porous structures [ 30 , 31 , 32 ] exhibits outstanding versality and feasibility for carrying information and manipulating multidimensional data.…”