A DMA Q800 (TA instruments) was used to perform the DMA analysis. Rectangular samples of 15 mm in length and 5 mm in width were cut from the PEFA film and fixed with the Film Tension clamps. A frequency of 1 Hz and a strain amplitude of 0.1 % was chosen over a temperature range of -50 to 150 °C with a heating rate of 5 °C min -1 . The glass transition temperature was measured from the loss modulus as the peak temperature within the transition region. The test was performed in duplicate.