Improved preparation of membrane surfaces for field-emission scanning electron microscopy

The separation characteristics of membranes depends greatly on their morphology. Thus, membrane investigation using scanning electron microscopy (SEM) is a standard method in membrane characterization. Careful specimen preparation methods are required to ensure excellent performance of field emission scanning microscopes and to minimize artifacts generated by the preparation process. For polymer samples with structural elements on a sub-micron scale, the surface structure can be significantly altered by energy impacts resulting from the preparation method. A method of conductive coating with reduced energy impact is demonstrated, which largely avoids the generation of artifacts during the coating process. This procedure generates images of membrane surfaces virtually artifact free.