A slippery molecular assembly allows water as a self-erasable security marker

Thirumalai, Rajasekaran ; Mukhopadhyay, Rahul Dev ; Praveen, Vakayil K. ; Ajayaghosh, Ayyappanpillai (2015) A slippery molecular assembly allows water as a self-erasable security marker Scientific Reports, 5 (1). ISSN 2045-2322

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Official URL: http://doi.org/10.1038/srep09842

Related URL: http://dx.doi.org/10.1038/srep09842

Abstract

Protection of currency and valuable documents from counterfeit continues to be a challenge. While there are many embedded security features available for document safety, they are not immune to forgery. Fluorescence is a sensitive property, which responds to external stimuli such as solvent polarity, temperature or mechanical stress, however practical use in security applications is hampered due to several reasons. Therefore, a simple and specific stimuli responsive security feature that is difficult to duplicate is of great demand. Herein we report the design of a fluorescent molecular assembly on which water behaves as a self-erasable security marker for checking the authenticity of documents at point of care. The underlying principle involves the disciplined self-assembly of a tailor-made fluorescent molecule, which initially form a weak blue fluorescence (λem = 425 nm, Φf = 0.13) and changes to cyan emission (λem = 488 nm,Φf = 0.18) in contact with water due to a reversible molecular slipping motion. This simple chemical tool, based on the principles of molecular self-assembly and fluorescence modulation, allows creation of security labels and optically masked barcodes for multiple documents authentication.

Item Type:Article
Source:Copyright of this article belongs to Springer Nature Limited
ID Code:130011
Deposited On:28 Nov 2022 11:55
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