The Instron 5944 Universal Tensile Testing Machine, equipped with a 500N load cell, was used to perform tensile test on PEFA films. 25 mm long and 5 mm wide strips were cut from a PEFA film and taped onto a C-shaped paper support. The latter helps in the placement and in the alignment of the sample, it is then cut before the test begins. The resulting gauge length was 10 mm, and a strain rate of 10 % min -1 was used. The specimens were conditioned for 48 h at 21 °C, 50 ± 3 % relative humidity (RH), and tested in the same condition. The reported data is an average of five samples.