Study of the conformational rigidity of polyelectrolytes by elastic neutron scattering: 1. Carboxymethylcelluloses in the intermediate momentum range

Abstract

Small angle elastic neutron scattered intensity l(q) by dilute solutions of a high molecular weight and low charge density carboxymethylcellulose (CMC) in D₂O, without added-salt has been measured. The variation of l(q) is proportional to q⁻² (q = momentum transfer) for q < q∗ , and to q⁻¹ for q > q∗ . The dependence on q⁻² shows that the distribution of the statistical units is Gaussian whereas the existence of q∗ provides the possibility of calculating the length of such a unit; according to the dependence on q⁻¹, we conclude that these units are rigid. The length increases with dilution and charge density, which agrees with our previous results obtained by viscosity.