Preparation of dual-emission polyurethane/carbon dots thermoresponsive composite films for colorimetric temperature sensing

Abstract Luminescent films have received great interest for chemo-/bio-sensing applications owing to their distinct advantages over solution-based probes, including their good stability; ease of storage, transport, and recycling; tunable shape and size; and non-invasive nature. In this study, mechanically stable polyurethane/carbon dot (PU/CDs) composite films with dual-emission for ratiometric temperature sensing were prepared. The films exhibited good light transmissivity, flexibility, and ductility. The obtained PU/CDs hybrid films with dual emission exhibited temperature response and reversible properties from 10 °C to 90 °C. At the appropriate reactive ratio of CDs to PU, the fluorescent color of the films shifted over a relatively large range from blue to green to yellow over a large temperature range. These findings indicate that the stretchable hybrid PU/CDs composite films could potentially be applied for colorimetric detection over a large temperature range (10 °C–90 °C). These materials thus have high application value for macroscopic dual-light temperature detection as well as further development of polymer composite modification.