2024-03-29T07:57:57Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/63602022-11-16T13:13:37Zcom_10259_4313com_10259_5086com_10259_2604com_10259_3592com_10259_3591com_10259.4_106col_10259_4314col_10259_3930
00925njm 22002777a 4500
dc
Guirado Moreno, José Carlos
author
Guembe García, Marta
author
García Pérez, José Miguel
author
Aguado, Roberto
author
Valente, Artur J. M.
author
Vallejos Calzada, Saúl
author
2021-12
The synthesis and preparation of 12 chromogenic polymers used to build an intelligent label for security paper applications are described. The process involves coating paper sheets with the polymers. Depending on the number of different polymers used in a combinatory way, a maximum of 1212 combinations is possible, thus creating a matrix that is practically impossible to counterfeit. Currently, most anticounterfeiting proposals for paper-based packaging and documents involve some sort of verification under ultraviolet radiation, and the requirement of additional equipment often relegates the end-user to a passive role. In contrast, in our approach, the combination of sensory polymers in an array gives rise to an invisible label, i.e., an owner cryptographic key, which becomes visible upon scattering a nitrite solution (e.g., spraying or using an impregnated foam roller) over the printed label on the security paper. For this purpose, a monomer containing an aromatic primary amino group and another with an activated aromatic ring are covalently bonded to a polymer with high affinity toward paper, consisting essentially of units of methyl methacrylate and 1-vinyl-2-pyrrolidone. Subsequently, the paper samples are coated with the resulting sensory chromogenic polymer. By spraying, painting, or staining an aqueous acid solution of NaNO2 (at least 1.20 g/L) and the chromogenic polymers, a well-defined color appears, because of the formation of an azo compound. This process provides users with a quick and facile authentication method without additional equipment and without affecting paper strength.
1944-8244
http://hdl.handle.net/10259/6360
10.1021/acsami.1c19228
1944-8252
Anticounterfeit
Papers
Azo-coupling
Sensory polymers
Colorimetry
RGB parameters
Chromogenic Anticounterfeit and Security Papers: An Easy and Effective Approach