A model graft copolymer material consisting of polystyrene (PS) chains grafted onto a poly(ethyl acrylate) backbone was studied by small-angle neutron scattering (SANS) and neutron reflectivity. This 28 wt% PS graft material exhibited a lamellar phase morphology; it also produced abnormal butterfly isointensity patterns in SANS when uniaxially strained. It is believed that the polydispersity in structure of the copolymers is critical in producing the unexpected lamellar morphology.