New Routes to High Resolution and Automated Polymer Morphology Microscopy via Scanning Electron Microscopy

Abstract Summary: Polymer morphologies are traditionally studied by transmission electron microscopy (TEM). With the use of appropriate contrast enhancing heavy metal stains, direct images of the morphology as well as of the lamellar structure of semi‐crystalline polymers can be obtained. Despite its clear strengths, this approach faces several challenges and difficulties: the laborious nature of ultra‐thin section preparation, high capital investment, and no obvious routes to high‐throughput. We propose an alternative approach to cover the major morphology imaging needs based on a new generation of high resolution scanning electron microscopes (SEM) that have been developed in recent years, and that does not rely on the need for ultra‐thin section preparation. The proposed approach is capable of not only determining the general phase morphology, but also to image details such as the lamellar structure with sufficient resolution. Our approach is based on the use of backscattered electron imaging at low accelerating voltages. The backscattered electron images show high contrast and information content that is comparable to TEM. The main advantage of our SEM based approach is the ability to examine a polished surface, which requires less demanding sample preparation than producing ultra‐thin sections. This opens the door to automated workflows where automated imaging, substantial productivity increases and high speed characterization options can be successfully realized. The successful approach is demonstrated for various polyolefin and engineering plastics samples.