Ayyappanpillai Ajayaghosh, Rajasekaran Thirumalai Kumaran
The present invention provides a novel fluorescent molecule having formula 1 which exhibit emission color change when in contact with moisture useful for the preparation of fluorescent paper, allowing self-erasable writing, security label for document authenticity, check and prevention of currency counterfeit. Compound of formula 1 when coated on paper results in blue emitting surfaces on which writing is possible using water as ink. The images undergo self-erasal after 6 hours making the paper reusable or instantly with hot air. The images are visible only on illumination with a UV lamp having wavelength 365 nm. The material can be coated on any document to create security label which changes color on touching with a wet surface or water pen and will go back to the native color when the moisture is dried off after a time frame. This strategy is used to create a security label for currency bills for checking original and fake currency notes or any other documents for authenticity. The technique is also useful for temporary writing on recyclable papers.