Applications of Scanning Electron Microscopy in Polymer Characterization

Scanning electron microscopy (SEM) is one of the most important tools for the characterization of polymer materials' microstructure and composition. First, it is easy to operate; then there are various electronic signals available which contain different sample information for SEM imaging; besides, there are little sample damage during SEM observation. In this work, the working principle of SEM was elucidated systematically. Also, a comparison was made between SEM and TEM with respect to working principle, resolution and magnification, view and depth of field, sample preparation, sample damage and pollution. Therefore, the advantages and features of SEM were highlighted. In addition, the experiment methods of SEM were illustrated in detail, including sample preparation, instrument parameter settings, operation skills and image treatment. The key factors which determines the quality of SEM image were revealed. The main applications of SEM in polymer characterization were introduced. Specifically, the secondary electrons imaging was used to investigate the microstructure of polymer composition, compatibility of polymer blends, crystal structure of polymer, morphology of polymer porous membrane, biocompatibility of polymer material, self-assemble behavior of polymer and so on. Besides, the backscattered electrons, characteristic X-ray, transmittance electrons were also used to reveal the morphology and composition information of polymer systems. The combination of SEM with Raman spectrometer and Focused ion beam and the in situ SEM techniques were illustrated. Finally, the recent trends of SEM development were prospected.