Static light scattering is an established method for the absolute determination of the weight average molar mass (Mw) of a polymer. The measurement is carried out without separation of the polymer solution in a light scattering detector cell. The measured quantity is the intensity of the scattered light (Excess-Rayleigh scattering), which is proportional to the average molecular size of the dissolved substance.
A series of measurements is performed with different concentrations (c) at various scattering angles (theta). The molecular weight average Mw is determined with by plotting the data and extrapolation of c and theta to zero (Zimm-plot). Other parameters derived from the Zimm-plot are the z-average of the radius of gyration and the second virial coefficient A2. One requirement is the knowledge of the refractive index increment (dn/dc) of the polymer in the solvent used.
Results provided to the client:
- absolute molecular weight average Mw
- radius of gyration z-average
- second virial coefficient A2
Request quote for sample testing
Customers from USA and Canada can use the online store and pay with credit card:
- Print and fill out the sample testing evaluation form, to be sent with the samples