标题： 具有伪装二维码的防伪标签，使用纳米腔中的聚合物分散液晶 显示英文标题

标题： Anti-counterfeiting tags with camouflaged QR codes on nanocavities, using polymer-dispersed-liquid-crystals

摘要： 伪钞制造不断增长的挑战，推动了对创新和复杂防伪策略和技术的需求。 许多解决方案集中在具有光学特征的标签上，这些特征部分或完全对人眼隐藏，从而阻止欺诈者。 在本文中，QR码被激光打印在一个预先涂有特定纳米腔的薄塑料箔上，该纳米腔由金属/绝缘体/金属/绝缘体（MIMI）多层结构组成。 这种超材料在光传输方面具有独特的特性，这是由于其特定的设计。 一层由特定向列相液晶掺入聚合物基质中制成的聚合物分散液晶薄膜，能够隐藏QR码，然后在特定热条件下才能读取。 制造了三种防伪标签，每种使用一种具有不同向列-各向同性转变温度的液晶。 向列相液晶和光学纳米腔独特光学特性的结合，导致了一种新型标签的产生，该标签显示两种不同的编码级别。 进行了包括水浸、弯曲测试和长时间加热在内的应力测试，确保了标签的长期稳定性。 实现的两种安全级别的防伪标签成本低廉，制造简单，并且由于其灵活性，可以轻松集成到包装和产品中。 显示英文摘要

摘要： Counterfeiting poses an evergrowing challenge, driving the need for innovative and sophisticated anti-counterfeiting strategies and technologies. Many solutions focus on tags characterized by optical features that are partially or completely camouflaged to the human eye, thus discouraging scammers. In this paper, a QR code is laser printed on a thin plastic foil previously coated by a specific nanocavity consisting of a metal/insulator/metal/insulator (MIMI) multilayer. This metamaterial possesses unique features in terms of light transmission that are due to the specific design. A thin layer of polymer dispersed liquid crystals, fabricated incorporating specific nematic liquid crystals in a polymer matrix, is able to camouflage the QR code that becomes, then, readable only under specific thermal conditions. Three anti-counterfeiting tags were fabricated, each using a distinct LC with its own nematic-isotropic transition temperature. The peculiar combination of the unique optical properties of nematic liquid crystals and optical nanocavities results in the creation of a novel type of tags showing two different encoding levels. Stress tests including water immersion, bending test, and prolonged heating have been performed ensuring the long-term stability of the tags. The realized two security-level anti-counterfeiting tags are cost-effective, straightforward to manufacture and, thanks to their flexibility, can be easily integrated into packaging and products.