Abstract The sample preparation technique in electron microscopy is very important but often overlooked. Because the preparation technique can influence the actual structure, care must be taken in order to avoid misinterpretation of images. This paper highlights various important factors in scanning electron microscopy (SEM) that must be considered in arriving at an optimal choice of condition for imaging in the study of polymer membranes. The same coating technique can produce different quality images depending upon the types of specimen. For example, for unsuded membranes platinum (Pt) coating gave a superior quality image to chromium (Cr) coating. However, for protein-fouled membranes Cr coating produced a superior image with more surface details. The advantages and disadvantages of low voltage SEM (LVSEM) is discussed in comparison with high voltage SEM.