Neutron scattering experiments on swollen, uniaxially stretched polymer networks

Neutron scattering measurements have been performed on uniaxially stretched, swollen polydimethylsiloxane (PDMS) networks produced by electron irradiation of a polydisperse melt. Upon stretching, the correlation length xi(L) becomes anisotropic varying continuously from a maximum value observed in the direction parallel to the stress, to a minimum value along the perpendicular direction. The observed angular dependence of xi(L) and that of the intensity scattered in the limit of zero scattering vector are very close to those predicted by a classical affine deformation model, suggesting that the connected superstructure of the swollen network is uniaxially deformed in a process that is essentially classical.