Methods for polymer synthesis and -characterization
In our own polymer synthesis laboratory, we can produce custom-made model polymers, for example, linear homo- and block copolymers, rings, branched polymers, such as combs and standard stars, as well as polymer grafted nanoparticles with defined molecular weight, functionality and narrow molecular weight distribution. The method of choice here is living anionic polymerization. For neutron scattering experiments, we routinely synthesize deuterium-labelled polymers based on deuterated momomers.
To undertake polymer characterization, the following methods are available:
• Size exclusion-chromatography: to determine relative and absolute molecular weights, e.g. molecular weight distribution.
• Osmometer: to determine the number average of the molecular weight, Mn.
• Multiple angle light scattering instrument and differential refractometer: used to determine the weight average molecular weight, Mw, and the specific refraction index increment, dn/dc.
• FTIR and UV/VIS spectrometer: used for the chemical characterization of monomers and polymers.
• Tensiometer using the drop method: for measuring surface and interfacial tension.
• Density meter using an oscillating U-tube: for the precise measurment of density in polymers, polymer solutions and solvents, in particular where it is necessary to calculate the exact contrasts in neutron scattering.
Additional important analyses, such as Maldi-TOF and NMR spectroscopy, are carried out by the Central Department for Chemical Analysis at Forschungszentrum Jülich.