Conditions for imaging emulsions in the environmental scanning electron microscope

Area of Science:

• Materials Science
• Physical Chemistry
• Microscopy

Background:

• Environmental scanning electron microscopy (ESEM) enables imaging of volatile and insulating samples in their natural state.
• ESEM offers higher resolution than optical microscopy for complex liquid systems.

Purpose of the Study:

• To evaluate ESEM as a tool for studying the structure and dynamics of emulsions and other liquid systems.
• To demonstrate the imaging capabilities of ESEM for micron-scale and smaller features in liquid samples.

Main Methods:

• Utilized Environmental Scanning Electron Microscopy (ESEM) for imaging various liquid systems.
• Analyzed image contrast based on the Stokes et al. (1998) model.
• Determined resolution limits influenced by sample motion and beam damage.

Main Results:

• Successfully imaged diverse liquid systems with micron-scale and smaller features.
• Observed clear discernment of system morphology and phase contrast consistent with theoretical models.
• Achieved resolutions of a few tens of nanometers under optimal conditions, outperforming optical microscopy.
• Identified thin films at liquid/gas interfaces, some too thin to obscure bulk sample structure.

Conclusions:

• ESEM is a powerful technique for analyzing the morphology and structure of complex liquid systems.
• ESEM provides high-resolution imaging capabilities for delicate samples without extensive preparation.
• The technique reveals interfacial phenomena and bulk structures with nanoscale resolution.