Phosphorescent Oxygen and Mechanosensitive Nanostructured Materials Based on Hard Elastic Polypropylene Films

It is well known that sensitivity of quenched-phosphorescence O₂ sensors can be tuned by changing the nature of indicator dye and host polymer acting as encapsulation and quenching mediums. Here, we describe a new type of sensor materials based on nanostructured hard elastic polymeric substrates. With the example of hard elastic polypropylene films impregnated with Pt-benzoporphyrin dye, we show that such substrates enable simple one-step fabrication of O₂ sensors by standard and scalable polymer processing technologies. In addition, the resulting sensor materials show prominent response to tensile drawing via changes in phosphorescence intensity and lifetime and O₂ quenching constant, K_q. The mechanosensitive response shows reversibility and hysteresis, which are related to macroscopic changes in the nanoporous structure of the polymer. Such multifunctional materials can find use as mechanically tunable O₂ sensors, as well as strain/deformation sensors operating in a phosphorescence-lifetime-based detection mode.