SPIN CONTRAST IN SANS OF POLYMERS IN SOLUTION

We present a small angle neutron scattering study of polymers in solut ion. The contrast between the scattering lengths of the polymer and th e solution is created by dynamic polarization of the nuclei in the sam ple. We used the spectrometer PAON at G5-3 of the LLB-Saclay-reactor O rphee which is a prototype of a SANS spectrometer using dynamic nuclea r polarization. The power of this method can be seen from the results obtained on two different samples: a solution of the homopolymer polys tyrene in orthoterphenyl, and a mixture of two homopolymers dissolved in toluene. We observed for the polystyrene sample the decrease in con trast at positive polarization and increase in contrast for negative p olarization. For the sample of the polymer mixture in solution we obta ined the different structure factors by taking the SANS spectra for di fferent polarizations. The interference term, obtained separately in t he same sample, confirms the mutual interaction.