Polymers encompass a large class of compounds comprising both natural and synthetic materials with a wide variety of properties. Polymeric materials compose a very wide range of materials such as plastics, amber, and rubber, and thus play an essential and ubiquitous role in everyday life. Electron microscopes allow for the better understanding of polymers and assist in the study of structure, morphology and properties.
Now more than ever, with more prominent nanostructuring of polymers, electron microscopy has become an indispensible tool to this research. The LVEM5 is used among other things to better understand the phase behavior and morphology of nanostructured polymers.
These sample types are normally a major challenge to image in an electron microscope due to inherent low contrast provided by their molecular composition. This is not the case when using a LVEM in polymer sciences applications. Issues with sample contrast are eliminated entirely.
Low energy electrons, as found in the LVEM microscopes, interact much more strongly with the sample than high energy electrons of classical TEM. Electrons in the LVEM are strongly scattered by organic materials resulting in exceptional differentiation of features. The density difference required in a sample to give a 5% contrast difference at 5 kV is a mere 0.074 g/cm3.
The LVEM5 electron microscope is the perfect solution for researchers in the structure and properties on polymers and polymeric materials. It operates with four distinct imaging nodes including TEM, SEM, STEM, and ED, and multiple imaging data can be accumulated for any single given sample at the microscale and the nanoscale. This means that information is available in both transmission (ultrastructure) and scanning (surface detail) modes.
The LVEM25 is built upon the same platform as the LVEM5, but operates at a slightly higher accelerating voltage allowing for an improvement to final image resolution. It is also capable of working with thin sectioned polymers prepared in the conventional way (~100nm) making it a true replacement of a conventional full sized TEM.
Whether it is for the greater understanding of self-assembling morphologies or processes of polymer blends and block copolymers, the LVEM electron microscopes are powerful and cost-effective options.
LVEM5 User Testimonial
The LVEM has proven to be particularly useful for the high contrast imaging of a wide variety of polymersWe have obtained images on a variety of systems including polyethylene single crystals, pentacene and TIPS-pentacene thin films, block copolymers, and poly(3,4-ethylene dioxythiophene).
The 5 kV operating voltage significantly increases the TEM image contrast, making it possible to minimize or avoid altogether the use of heavy metal stains that are usually a necessary evil in polymer transmission electron microscopy. These metals, including osmium, ruthenium, tungsten, and uranium, are difficult to work with in the laboratory, can present safety hazards, and may interact with the sample in a way that obscures its native structure.
Another significant advantage of the LVEM is the small chamber size, making it possible to rapidly change samples. Its small footprint makes it possible to locate directly in the lab, providing nearly immediate feedback about sample nanostructure.
Dr. David C. Martin
Karl W. and Renate Böer Professor
and Chair of Materials Science and Engineering
Department of Materials Science and Engineering
The University of Delaware