Complex global supply chains, counterfeit products or the concept of Circular Economy demand the identification (ID) of arbitrary objects. Smart additives in form of (sub)micron sized particles that carry a unique code, provide a promising approach to overcome the drawbacks of RFID and barcode labels and thereby contribute to a more sustainable world. Going beyond optical signal carriers, magnetic signals can be transmitted through many materials that would not allow optical information to pass. The possibility to read out the magnetic signals out of a certain depth even when covert within dark solid objects, enables an easy incorporation of the marker during production of the materials and additionally protects the marker against environmental harm or easy reveal. Thereby, objects in different application fields could be equipped with such a smart additive (Fig. 1). In this work it is presented that nanostructured micron-sized particles (so called supraparticles) have the potential to be spectrally encoded with more than 77 billion magnetic codes as resolved by magnetic particle spectroscopy (MPS). Thereby, a magnetic identification taggant, that does not rely on the spatial arrangement of magnetic particles, is established. A chemical synthesis strategy was developed that enabled the control of nanoparticle-nanoparticle interactions within multi-hierarchical supraparticles in order to obtain a large number of different magnetic codes. This principle will be vividly demonstrated in analogy to a musical ensemble in order to explain the readout technique MPS. Additionally, it is shown that a luminescent code can be united within such supraparticles, yielding dual-spectrally encoded supraparticles.

Object identification with micron-sized magnetic supraparticle taggants

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.