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Low-Angle-Dependent Anticounterfeiting Label Decoded by Alcohol Tissue Wiping Based on a Multilayer Photonic Crystal
Suli Wu1, Jinjian Nan1, Yue Wu1
1State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2# Linggong Road, Dalian 116024, P. R. China.
ACS Applied Materials & Interfaces
|June 6, 2022
Summary
This study introduces a novel photonic crystal (PC) composite structure for advanced anticounterfeiting. The material uses tunable structural colors and a reversible alcohol-triggered encryption method for secure labeling.
Area of Science:
- Materials Science
- Optics
- Nanotechnology
Background:
- Photonic crystals (PCs) offer tunable photonic stop bands and structural colors, making them suitable for anticounterfeiting applications.
- Existing anticounterfeiting methods often lack robust, visually dynamic security features.
- The development of advanced materials with controllable optical properties is crucial for combating product fraud.
Purpose of the Study:
- To design and fabricate a composite photonic crystal structure for effective anticounterfeiting.
- To develop a novel, alcohol-triggered reversible encryption and decryption mechanism for security labels.
- To evaluate the stability and visual characteristics of the structural color for information display.
Main Methods:
- Fabrication of a multi-layered composite structure comprising a CdS photonic crystal (PC) layer and a polymer-based layer (inverse opal PC and disordered porous layer).
- Investigation of the optical properties, including structural color and transmittance, under varying incident angles and after alcohol wiping.
- Design of a double-sided label with distinct encryption patterns for enhanced security.
Main Results:
- The composite PC structure exhibits vivid, low-angle-dependent structural color in the decoded mode, with minimal color shift from 5° to 45° incident angles.
- An alcohol tissue effectively decodes the hidden pattern by increasing the transmittance of the upper polymer layer due to refractive index matching.
- The reversible encryption/decryption process and stable structural color demonstrate significant potential for daily anticounterfeiting.
Conclusions:
- The designed composite PC serves as an effective anticounterfeiting label with a pattern decoded by alcohol wiping.
- The material offers a stable, visually appealing structural color and a simple, reversible security feature.
- The proposed double-sided label design enhances anticounterfeiting capabilities, showing great application potential.
