Low Vacuum Scanning Electron Microscopy for the Characterization of Polymers enabling in situ, 3D and Correlative Investigations

Low Vacuum Scanning Electron Microscopy (LVSEM) is an alternative to conventional scanningelectron microscopy (SEM), which requires a high vacuum in the specimen chamber. LVSEM usesimaging gases like air, water vapor or nitrogen at pressures of about 10 – 200 Pa. The low vacuummode, which is also called variable pressure (VP) mode, has the advantage that even electricallynonconductive specimens, like polymers, can be investigated without applying an electricallyconductive layer. This enables in situ investigations of specimens, where the manipulation of a samplecan be imaged delivering a film and a series of tiff files. Thus dynamic experiments can be performedlike in situ tensile testing [1] or in situ ultramicrotomy [2] (i.e. serial block-face scanning electronmicroscopy, SBFSEM), where an ultramicrotome is built in the specimen chamber of an LVSEM,enabling serial sectioning and imaging of specimens and as a result 3D reconstructions of a volume ofinterest. Additionally the low vacuum mode is fundamental for the combination of SEM and Ramanspectroscopy, where high resolution imaging can be combined with chemical assessment on the samesite of a specimen. In this work results gained with the system RISE (Raman Imaging and ScanningElectron Microscopy), which combines the SEM Zeiss Sigma 300 VP with a Raman microscope fromWITec (Germany), are presented (Figure 1).