Bio-derived chlorophyll dye doped cholesteric liquid crystal films and microdroplets for advanced anti-counterfeiting security labels

Abstract

Herein, we have shown security codes based on an advanced anti-counterfeiting material that are diffi-cult to duplicate and are substantially distinct from the present technology. The anti-counterfeiting material can be made by dispersing green synthesized chlorophyll from spinach leaves into cholesteric liquid crystal (Red, Green and Blue reflections). The resultant anti-counterfeiting material reflects color in daylight (Red/Green/ Blue) due to the reflection property of CLCs and magenta color in UV light due to the fluorescence property of chlorophyll. Furthermore, we have shown that anti-counterfeiting mate-rial confined to spherical microdroplets produced by glass capillary microfluidic approach exhibit dual -mode display and security ink properties under daylight and ultraviolet light, including authenticate/ non-authenticate QR codes, implying their potential applications in anti-counterfeiting technologies for the protection of valuable objects. These color variations are easily detectable in real time and may be used to create anti-counterfeiting patterns with color changes in both reflection and fluorescence modes. Because of the easy technique, we believe this can give a new platform for numerous security and color-based applications that is more cost-effective and environmentally friendly than traditional approaches.(c) 2022 Published by Elsevier B.V.