Background color dependent photonic multilayer films for anti-counterfeiting labeling.

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Developing advanced anti-counterfeiting measures is crucial for product security.
• Traditional methods often lack dynamic visual indicators.
• Humidity-responsive materials offer novel security features.

Purpose of the Study:

• To present a novel anti-counterfeiting security film concept.
• To utilize humidity-induced color changes for QR code visualization.
• To develop color-tunable one-dimensional photonic crystal (1D PC) films.

Main Methods:

• Fabrication of 1D PC films on polyethylene terephthalate (PET) substrates.
• Sequential alternate layer deposition of specific polymers: poly(2-vinylnaphthalene-co-benzophenone acrylate) (P(2VN-co-BPA)) and quaternized poly(4-vinylpyridine-co-benzophenone acrylate) (P4QP-51%).
• Laser printing of a hidden QR code onto the PC film.

Main Results:

• The 1D PC films demonstrated reversible and reproducible color transitions.
• Full visible spectrum colors were observed on a black background in high humidity.
• Yellow, magenta, and cyan composite colors appeared on a white background.
• A hidden QR code was successfully integrated for enhanced security.

Conclusions:

• The developed colorimetric 1D PC films are effective for anti-counterfeiting applications.
• Humidity-induced color changes provide a dynamic security feature.
• These films can serve as advanced anti-counterfeiting labels and for information storage.