A new preparation technique for examination of polymers in the scanning electron microscope.

Abstract

It is well known that electrically nonconducting specimens can be examined in a scanning electron micro-scope with a reasonable degree of success, either by prior evaporation of a thin metal film or decrease of the accelerating potential of the incident electron beam, whenever the concomitant decrease in resolution is acceptable. Considerable simplification in the preparation of polymer specimens has been achieved by spraying them with an antistatic aerosol, used in the textile industry, so that cellulose, protein (but not mammalian keratin), polyacrylonitrile, polyamide, polyester, polyethylene, polypropylene and polytetrafluoroethylene materials can be examined at the highest potential available in the Cambridge Stereoscan, namely 20 kv. In particular, our method reduces the hazards of modifications caused by the repeated exposure of biological materials to the effect of low pressure, during the usual evaporation of a thin metal layer and subsequently in the scanning electron microscope. It was successfully applied to the examination of small organisms, after drying and/or fixing according to the standard specimen preparation methods accepted in orthodox transmission electron microscopy.