Polymer-nanotube systems are extremely interesting because small additions of nanotubes can dramatically change the conductivity, rheology, and many other properties. In addition to potential applications in materials science, nanotubes are mesoscale analogs of semi-flexible polymers and offer a unique perspective on macromolecular science. In a practical sense, the work addresses issues associated with the flow processing of polymer-nanotube composites. Using a variety of unique instrumentation available at NIST, such as small-angle neutron scattering, flow light scattering, and electron microscopy, we study the equilibrium and nonequilibrium structure and dynamics of polymer-nanotube solutions and blends.