Transmission electron microscopy methods for the determination of void content in polyimide thin film nanofoams

Transmission electron microscopy (TEM) has been used to determine the porosity of polymer nanofoams produced by thermal decomposition of the thermally labile component of different copolymers. The results are compared with those obtainable by i.r. spectroscopy and density gradient methods, showing quantitative agreement for small pore sizes. TEM permits much higher spatial resolution than i.r. spectroscopy and is better suited to structures which scatter strongly at i.r. wavelengths. © 1995 Elsevier Science Ltd.