Sol Methods

     • Light Scattering http://www.brookhaveninstruments.com/

          - Quasielastic (dynamic)

          - Static

There are two methods used in light scattering to characterize our suspended particles. One of these is static and the other dynamic light scattering.

In dynamic light scattering (DLS), the time dependence of the intensity fluctuation is most commonly analyzed using a digital correlator. Such a device determines the intensity autocorrelation function which can be described as the ensemble average of the product of the signal with a delayed version of itself as a function of the delay time. The ¨signal¨in this case is the number of photons counted in one sampling interval. At short delay times, correlation diminishes to zero and the exponential decay of the correlation function is characteristic of the diffusion coefficient of the particles. In our case, we use a Brookhaven BI-9000AT.

Static light scattering is sometimes referred to as classical light scattering or Rayleigh scattering and can be used to characterize the average particle size of our particles or aggregates. Classical light scattering involves measuring the amount of light scattered by a suspension at some angle relative to the incident laser beam. We also use the Brookhaven instrument to make these measurements.

For further review of this subject one can read the “wiki” scattering site.