C. Reinhardt, G. Meyers
Keywords: atomic force microscopy, AFM, sample preparation, microtomy, automation, microscopy
Summary:To develop structure-property relationships for polymeric systems it is critical to understand the underlying morphology because of processing. This information is typically obtained using AFM, SEM, or TEM of cross-sections or thin sections from samples in an experimentally large design space such that morphological parameters (e.g., impact particle size, shape, distance) can be quantified and trends established to predict performance. AFM caters to this workflow since sample preparation is much less demanding, e.g., not requiring heavy metal staining or thin sectioning. Some aspects of automation for this workflow are available from AFM vendors. Automated or unattended data acquisition is available with customized recipes for multiple samples or sample locations. Automated image or force curve data analysis suites are also available from software vendors. However, there is little in the way of automated sample preparation to front-end this workflow. We have invested in the development of an automated sample preparation process that offers substantial time savings enabling AFM to manage large experimental designs. This talk will discuss the motivation for this workflow considering the polymer blend morphology characterization and migration of such from electron microscopy to AFM. This will include the design and construction of multi-sample stages, sample holders, preparation holders, and cryogenic milling as well as continuous improvements in the evolution of this capability. Consideration will be given to issues associated with unattended and automated acquisition on commercial AFMs as well as image post-processing that have come from the implementation of the automated sample preparation process.