DYNAMIC PROTON POLARIZATION ON POLYMERS IN SOLUTION - CREATING CONTRAST IN NEUTRON-SCATTERING

Dynamic nuclear polarisation (DNP) as an alternative or additional met hod to create contrast in neutron small angle scattering has been inve stigated with emphasis on the study of polymers in solution, The need for high polarisations imposes specific requirements on the sample and its environment. Vitreous beads have been used as samples. Nuclear re laxation times show that they contain dissolved air. Parasitic scatter ing from the solvent is observed, probably arising from nanometer air bubbles. DNP is shown to be useful, in particular for samples that con sist of mixtures of hydrogen-free and hydrogen-rich molecules, where t he different molecules can be highlighted by changing the polarisation .