Visualization Detection of Ultralow Temperature Based on Flexible Cross–linked Polymer Systems

Abstract Ultralow temperature storage has sparked considerable attention with the development of the economy, showing promising applications ranging from biomedical to national defense and other fields. However, the development of ultralow temperature detection is constrained by the brittleness of current materials at low temperatures and the complexity of detection techniques. Consequently, the challenge exists in finding efficient solutions to material tolerance issues and achieving rapid detection of ultralow temperature. Herein, a novel flexible cross–linked polymer TPTA@PU film with long afterglow, high phosphorescence quantum efficiency, and excellent mechanical properties are successfully fabricated. Interestingly, the obtained TPTA@PU films demonstrate a notable thermoresponsive behavior, with the afterglow color shifting rapidly from blue to green within the temperature ranges from 80 to 280 K. Additionally, there is a positive linear correlation between the RGB values of the afterglow color and the corresponding temperature. Based on these prominent features, an ultralow temperature sensor is realized by utilizing TPTA@PU films as thermoresponsive elements. This work can be expected to provide more inspiration and possibilities for using RTP materials in a more cutting‐edge field.