Conclusion

In the past, TEM was the only technique suitable for the direct observation of nanoscopic objects such as lamellae in a semi-crystalline polymer or fibrils in a crack. Now, scanned probe techniques such as AFM and SEM are beginning to rival it in this respect. The potential of SEM, in particular, is gradually outstripping its traditional role as a low-magnification, high-depth-of-field tool, while retaining the advantage of relatively easy sample preparation. However, SEM and AFM are mainly surface techniques, and TEM remains indispensable for studying the local three-dimensional organization of polymers by simultaneous diffraction and imaging, for example. Moreover, modern TEMs offer imaging and analysis capabilities with spatial resolution and sensitivity far superior to those of early instruments, and still far superior to those of SEM. That said, all the techniques mentioned are constantly...