Calculation of Elastic Small-Angle Neutron Scattering from Labeled Gels

Abstract

Crosslinked network polymers which have been labeled around the crosslinks are essentially triblock copolymers connected in groups of three or four at the ends. Although such networks are infinite in extent, it has been possible to calculate elastic small-angle neutron scattering (SANS) patterns for them after making reasonable assumptions about correlations in the networks. It is shown that the SANS from such crosslinked labeled networks is indistinguishable from the SANS of long-branched polymers made up of the same triblock copolymers. In fact, little difference is calculated between the SANS of the networks and the SANS of the constituent triblock copolymers. The calculated SANS of three different-long branched polymers are compared with the SANS of the triblock copolymer. It is shown that SANS of gels in which all of the crosslinks are labeled depends only on the extent of labeling and on the radius of gyration of the constituent block copolymer.