SCANNING VOL. 24, 75–85 (2002)
Received: January 28, 2000
Accepted with revision: September 18, 2001
© FAMS, Inc.

Conditions for Imaging Emulsions in the Environmental Scanning Electron Microscope

R. G. Mathews and A. M. Donald

Polymers and Colloids Group, Department of Physics, Cambridge University, Cavendish Laboratory, Cambridge, U.K.

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Summary: Environmental scanning electron microscopy (ESEM) is a technique capable of imaging volatile and/or insulating samples in their natural state, without prior specimen preparation. It is thus a powerful potential tool for the study of the structure and dynamics of emulsions and other complex liquid systems, at a resolution greater than that obtainable by conventional optical microscopy. We present images of a variety of liquid systems containing micron-scale and smaller features. The morphology of these systems may be clearly discerned. The contrast observed between the liquid phases was consistent with the model proposed by Stokes et al. (1998). The limits of resolution were determined by sample motion and by beam damage effects; under optimum conditions, resolution of a few tens of nanometers was obtained. This compares favourably with conventional and confocal optical microscopy. In some samples, thin films (solid or liquid) could be observed at the liquid/gas interface. Some of these films were so thin that they did not completely obscure the underlying structure of the bulk sample.

Key words: environmental scanning electron microscopy, secondary electron contrast, complex fluids, liquid thin films

PACS: 07.78+s, 61.16.Bg, 61.80-x, 79.20.Hx

Address for reprints:

A. M. Donald
Polymers and Colloids Group
Department of Physics
Cambridge University
Cavendish Laboratory
Madingley Road
Cambridge CB3 OHE, U.K.
e-mail: rgm28@phy.cam.ac.uk