Small-angle neutron scattering study on charged gels in deformed state

The structure of weakly charged temperature sensitive gels has been investigated in deformed state by means of small-angle neutron scattering (SANS). At low temperatures where the gel is in a good solvent, the scattered intensity pattern was isotropic even for deformed gels. When the temperature was raised to 42 °C, the so-called butterfly pattern, i.e., a prolate-shaped scattered intensity pattern with respect to the stretching direction, appeared in the deformed gels. With a further increase in temperature to 46 °C, a scattering maximum was observed. In the case of undeformed gel, the scattering pattern had a circular maximum with q = q_m, where q is the magnitude of the scattering vector and qm is the q value at the scattering maximum. On the other hand, the scattering pattern became oblate for the deformed gel, i.e., q_m,y < q_m,x, where the subscripts y and x indicate the stretching and perpendicular directions, respectively. These changes of the SANS intensity patterns are discussed by decomposing it into the thermal fluctuations and the static inhomogeneities.