EMSL Analytical provides testing services for the characterization and analysis of a wide array of nanoparticles.  The laboratory has provided nanoparticle studies for the Federal Government as well as Fortune 500 Companies. 

EMSL’s nanoparticle laboratory is staffed with renowned scientists who have access to the most advanced instrumentation available.  It includes a JEOL Scanning Transmission Electron Microscope (STEM) as well as multiple Transmission Electron Microscopes (TEM) that are capable of Energy Dispersive X-Ray Analysis (EDXA) and digital imaging. In addition, EMSL’s analytical instrumentation includes, but is not limited to: Scanning Electron Microscopes (SEM), Auger Electron Spectroscope (AES) and a High Voltage (200kV) Transmission Electron Microscope (TEM) all equipped with state of the art Energy Dispersive X-Ray Analyzers (EDXA).

The scientists at EMSL routinely harness the power of this diverse inventory of scientific instrumentation to identify and quantitate nanoparticles and carbon nanotubes for:

  • • Morphology
  • • Chemical Composition
  • • Particle Size
  • • Distribution
  • • Presence as an Environmental Contamination

Particle Size and Zeta Potential

Sub-micron or nanometer particles have emerged as a continuously growing field, covering a wide range of applications in chemistry, physics and material science, ranging from electronic, optical and mechanical devices to drug delivery and encapsulation.  As particle sizes approach molecular dimensions, physical and optical properties of a material will change.  A reliable, accurate and rapid means of particle size measurement and materials characterization is, therefore, a very important capability.

Dynamic Light Scattering (DLS) is a method suitable for measuring the size of the particles in the low micron and nanometer range (0.6 - 5000 nm).  The principle of this method is based on the change in intensity with time of light scattered from particles in Brownian motion and suspension.

The stability of particles in suspension is also an important factor.  It is strongly influenced by the electrical charges that exist at the particle-liquid interface.  Zeta potential of a particle is the overall charge that it acquires in a particular medium.  It is therefore an indication of the particle-particle repulsive force and can be used to predict the long-term stability of a product in suspension.  If all the particles in suspension have a large negative or positive zeta potential, they will tend to repel one another, resulting in a low tendency for the particles to agglomerate.  However, where particles have low zeta potential values, there is no force to prevent the particles from agglomerating and flocculating.