Heat-resistant luminescent films: a thermal study of fluorene/thiophene copolymer-elastomer blends

The luminescent properties of conjugated copolymers could be harmed due to thermo-oxidative degradation, limiting their applications. To overcome these problems, incorporating flexible and stable polymers, such as elastomers, is a simple and advantageous approach to obtaining luminescent, flexible, and thermo-resistant films. Thin films based on blends of a luminescent thiophene/fluorene copolymer (PTPF) and two elastomers, nitrile rubber (NBR) and natural rubber (NR) were prepared by a straightforward method, and thermal degradation tests were carried out at different temperatures. Oxidized structures in the PTPF chains can be observed using FTIR, and up to 330 °C for NR and to 395 °C for NBR, no significant changes were observable, however, over these temperatures, the blends also lost their luminescent properties. The characterization of the films at increasing degradation stages points to possible mechanisms associated with the degradation processes suggesting a strategy to guarantee incremented thermal protection to the conjugated material, maintaining its structural and optical properties at higher temperatures than ambient temperature, making these flexible-luminescent films interesting for applications in which the thermal resistance is a key factor to consider.

Graphical abstract

Thermal degradation study and obtention of thermo-resistant luminescent films based on blends of thiophene/fluorene copolymer and nitrile or natural rubber