Small-angle neutron scattering investigation of topological constraints and tube deformation in networks

The effect of topological constraints on the microscopic deformation of network chains in a statistically cross-linked rubber under uniaxial deformation is addressed by small-angle neutron scattering (SANS) on labeled paths in a network. The observed SANS patterns exhibit a pronounced transition from elliptical to lozengic shapes. Within a tube approach for the constraining potential the scattering function is calculated in the 2D detector plane. Excellent agreement between the statistical mechanical model and the experimental results is obtained.