Polydiacetylene Sensor Arrays as Multimodal Tamper Indicators

Sandia National Laboratories (SNL) is developing a sensing suite of polydiacetylene (PDA) materials for tamper indication. PDAs represent a unique class of polymeric materials that provide drastic visible color changes when exposed to an assortment of different stimuli. Generally, tamper-indicating technologies have only incrementally improved over decades, while adversaries continually advance in their methods to defeat these technologies. Therefore, the tamper-indicating technology toolbox should also continually advance. Current sensing technologies primarily (but not exclusively) rely on visual examination of tamper-indicating devices (TIDs) to detect mechanical changes in the TID; however, visual inspection may not always be useful at detecting changes that result from other methods of attack. The PDA sensing suite described here can visibly change color not only when a TID is attacked via mechanical means, but also when chemical, electrical, and thermal means are used to attack. The multi-functional properties of PDAs offer a noteworthy benefit for detecting a variety of adversarial means of attack, thus increasing the level of difficulty and resources adversaries would need to defeat a TID.