Summary: A hard‐segment homopolymer (HSH) and segmented poly(ester urethanes) (PESU) were studied by TEM to estimate their stability against electron‐beam irradiation. The bright‐field image and electron‐diffraction modes in TEM and optical polarised microscopy were used. It is shown that both soft and hard segments are sensitive to the electron beam. None of the films was stable enough to register an electron‐diffraction pattern without damage.
Electron‐diffraction pattern taken from the film of hard‐segment homopolymer crystallised at 100 °C from DMF: (a) the pattern registered immediately; (b) the pattern registered after 5 s of exposure in the TEM at the same place.
