LASER LIGHT SCATTERING

Laser Light Scattering is one of the most important techniques for the characterization of polymers and particles in solution. Based on different physical principles, a variety of Laser Light Scattering techniques has been developed. Some of these Laser Light Scattering techniques are presented in the following listing.

1) Static Laser Light Scattering Techniques

Typical molar mass range: ca. 103 g/mol to ca. 109 g/mol
Typical particle size range: ca. 10 nm to ca. 500 nm
Multi Angle Static Laser Light Scattering - MALS
With Multi Angle Static Laser Light Scattering. Molar mass and size can be calculated not only for smaller but also for bigger macromolecules and even nanoparticles. In Multi Angle Static Laser Light Scattering the data of a series of different scattering angles is plotted into the Zimm Plot and the resulting function allows the determination of molar mass (slope of curve at angle 0° angle) and size (intercept value of graph with y-axis). Thus Multi Angle Static Laser Light Scattering is capable of providing precise and correct molar mass and size values for macromolecules and nanoparticles.

2) Dynamic Laser Light Scattering Techniques

Typical particle size range: ca. 1 nm to ca. 5000 nm

Dynamic Laser Light Scattering - DLS: Dynamic Laser Light Scattering is also called Photon Correlation Spectroscopy (PCS) or Quasi Elastic Laser Light Scattering (QELS). Dynamic Laser Light Scattering is primarily used for the determination of particle size of macromolecules and particulates in solution. In Dynamic Laser Light Scattering the fluctuation of the scattered light caused by the Brownian Motion of the molecules, is detected by a photon detector. The collected data is used to establish a correlation function from which the Hydrodynamic Radius can be calculated. Molar mass can only be calculated from the hydrodynamic size when certain assumptions concerning the conformation (sphere, rod, etc.) are made.
 
Multi Angle Dynamic Laser Light Scattering - DLS: In most cases Dynamic Laser Light Scattering is done at a 90° scattering angle. In some complex mixtures and when high or low sample concentrations are present, also other scattering angles (e.g. back scattering angles) can be used. The most advanced Dynamic Laser Light Scattering technologies work with multiple angles to provide a maximum of information concerning the sample.

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Light Scattering  |  Laser Light Scattering
Static Light Scattering  |  Multi-Angle Light Scattering  |  Dynamic Light Scattering