Flexible polyarylene ether nitrile containing pendant carboxyl groups/Eu(III) fluorescent films with high thermal stability and mechanical strength

A series of flexible and transparent polyarylene ether nitrile with pendant carboxyl groups/Eu(III) fluorescent films were successfully prepared, and characterized by scanning electron microscopy, energy-dispersive spectroscopy, thermogravimetric analysis, tensile test, ultraviolet–visible absorption and fluorescence spectroscopy. The results showed that the films possess high thermal stability (5% weight loss temperatures over 425 °C) and high mechanical strength (tensile strengths exceeding 90 MPa). Furthermore, all the films exhibit a relatively high transmittance in the visible region, and also show an excellent macroscopic flexibility, so that they can be easily bent and curled. This is mainly attributed to the superior performance of the polymer matrix. The photoluminescence results indicated that the films emit an intense red light at 617 nm under ultraviolet excitation, which is attributed to the 5D0 → 7F2 transitions of Eu(III) ions.

► PEN with pendant carboxyl groups/Eu(III) fluorescent films were prepared. ► The films are transparent and highly flexible. ► The films exhibit high thermal stability and high mechanical strength.