Polarized neutron diffraction experiments will be performed on a series of conjugated polymers with variable alkyl substitution groups. The use of D7 will allow us to resolve the coherent scattering function in hydrogenated polymer samples as a function of temperature. The resulting diffraction patterns will also be combined with x-ray diffraction experiments and these will all be collectively compared to scattering predictions from ongoing MD simulations. The results of this study will provide a direct evaluation of the effect of alkyl substitutions on the melt conformation of polythiophene polymers and on their electronic properties.