Plasmonic Nanogels for Unclonable Optical Tagging.

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Developing secure and verifiable identification methods is crucial for anticounterfeiting.
• Plasmonic nanostructures offer unique optical properties for sensing and tagging applications.
• Functional gel coatings provide a versatile platform for creating complex material architectures.

Purpose of the Study:

• To fabricate novel functional gel coatings with randomized physical and chemical patterns for unclonable optical tags.
• To investigate the dual encoding ability of these patterned gel coatings.
• To explore their potential for anticounterfeiting applications.

Main Methods:

• Fabrication of ultrathin responsive gelatinous polymer films with uniformly adsorbed plasmonic nanostructures.
• Swelling-mediated reconstruction into a randomized network of interacting folds.
• Characterization of electromagnetic hotspots and their correlation with topology and chemical distribution.
• Measurement of surface-enhanced Raman scattering (SERS) enhancement.

Main Results:

• Demonstrated the creation of randomized physical and chemical patterns in gel coatings.
• Observed bright electromagnetic hotspots within the folds of the reconstructed gel.
• Revealed a strong correlation between topology, chemical distribution, and near-field electromagnetic enhancement.
• Achieved a nearly 40-fold increase in SERS enhancement compared to pristine gels.
• Established dual topo-chemical encoding for multidimensional optical tagging.

Conclusions:

• The developed folded plasmonic gel acts as a multidimensional optical taggant with dual topo-chemical encoding.
• The spontaneous folding process and resulting patterns are virtually impossible to replicate, offering robust anticounterfeiting capabilities.
• This technology presents a promising solution for creating highly secure and unclonable optical tags.