Scattering properties of rod-coil and once-broken rod block copolymers

Static and dynamic scattering properties of(a-b) diblock copolymer chains having different architectures are discussed in the framework of the random phase approximation (RPA)I The case of a symmetric diblock (50/50) in a solvent satisfying the zero average contrast condition,in the semidilute regime, is considered in detail. We, in particular, calculate the scattering intensity and the relaxation times of linear rod-coil and once-broken rod copolymer chains and compare the results to those already known for classical linear diblock copolymers and to more recent results on ring diblock systems. Both static and dynamic scattering properties show that the microphase separation.(MST) occurs for the symmetrical case at (chi PhiN, q(m)R(gt)) =(17.7, 2.9), (8.5, 2.2), and (8.2, 2.5) for ring coil-coil, linear rod-coil, and once-broken rod diblocks, respectively. These results are compared with those for linear diblock copolymers where the MST occurs at (10.5, 2).