Block copolymer morphologies are being used as templates for applications that require nanometer-scale order. However, many applications require nanometer-scale order over large areas. We find that the both the long-range order and the degree of domain segregation in a semicrystalline, amphiphilic block copolymer thin film can be improved by blending it with an amorphous homopolymer that interacts strongly and selectively with the crystallizable block. Small angle neutron scattering (SANS) measurements show that the order in a weakly segregated poly (ethylene oxide-propylene oxide-ethylene oxide) (PEO-PPO-PEO) template is significantly improved when blended with poly (acrylic acid) (PAA). This increased ordering is observed both below and above the melting temperature of the crystalline block. Strongly selective hydrogen bonding interactions between PAA and the ether oxygen in PEO coupled with repulsive interactions between PAA and PPO improve the segregation strength between the domains, resulting in improved long-range order.