A Q2000 Differential Scanning Calorimeter (TA Instruments, New Castle, DE, USA) was used to determine the calorimetric glass transition temperature (T g,DSC , defined by the onset temperature) for each material. For each measurement 2 -3 mg of sample material were placed in hermetically sealed aluminium pans under a constant flow nitrogen atmosphere (flow rate 50 ml min -1 ) and heated at 3 K min -1 from room temperature to above the melting temperature T m , of the material. Following the melt of the polymer, the samples were cooled to approximately 213 K at a rate of 3 K min -1 . The samples were subsequently heated again through T g at a rate of 3 K min -1 . The modulation frequency was 0.003 K s -1 . The temperature and heat flow of the instrument were calibrated using indium (T m = 430 K, ∆H fus = 29 J g -1 ).