The enhancement of the security for banknotes with nano anti-counterfeiting paper by national researchers

According to ISNA, photo-chromic materials refer to a category of materials which react against specific range of light and change color. The usage of these materials in photo chromic lenses of glasses is their most famous application. 

Another application of photo chromic materials is in producing banknotes with high safety. When these kinds of paper are exposed to ultraviolet light, their color will change which can be used as a security mark to identify whether banknotes are fake or not.

Dr. Alireza Mahdavian, Iran Polymer and Petrochemical Institute faculty member reported on performing this research and said, "A simple and green method has been introduced to prepare a new cellulose paper with multiple response property in this research project."

Describing the used method of this project for the production of smart paper a simple and green one, he noted, "Moreover, the produced paper has higher photo-chromic performance than the similar samples."

Referring to the phenomenon of negative photo-chromism as an unwanted phenomenon observed in previous studies, Mahdavian added, "In previous attempts and studies, phenomenon of negative photo-chromism was mentioned because the photo-chromic compounds entered the cellulose matrix, and in many researches, the immigration and instability of chromic compounds were reported in final products."

Polymer and Petrochemical Institute faculty member added, "The mentioned defects have been fixed in this research which has led to increased efficiency and the improvement of the intelligent behavior of the produced paper."

He emphasized, "In this study, photo-chromic particles dispersed in water were prepared in dimensions of about 70 nanometer." Then he continued, "The small size of nano-particles has led to increased efficiency and output of chemical reaction in nano –particles with cellulose and the protection of photo-chromic color against destructive and malicious agents."

Mahdavian explained, "In the research, the photo-chromic compound was first prepared based on spiropyran. Then, the acrylic base polymers were made by the process of emulsion copolymerization.  Finally, the produced photo-chromic polymer entered the substrate of cellulose during the chemical process."

The researcher, emphasizing that this nano- structured paper has the property of anti-counterfeiting, noted, "The paper made in the experimental phase can be used for making banknotes with high security." 

These studies were carried out by Dr. Mahdavian, the member of Iran Polymer and Petrochemical Institute faculty, Amin Abdollahi and Jaber Keyvan Rad the graduates of master's degree at Iran Polymer and Petrochemical Institute, and the results were published in the journal of Carbohydrate Polymers."