  We investigate the behaviour of randomly cross-linked (co)polymer blends
using a combination of replica theory and large-scale molecular dynamics
simulations. In particular, we derive the analogue of the random phase
approximation for systems with quenched disorder and show how the required
correlation functions can be calculated efficiently. By post-processing
simulation data for homopolymer networks we are able to describe neutron
scattering measurements in heterogeneous systems without resorting to
microscopic detail and otherwise unphysical assumptions. We obtain structure
function data which illustrate the expected microphase separation and contain
system-specific information relating to the intrinsic length scales of our
networks.
