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Introduction. Block copolymers show a rich variety of spatially periodic nanostructures due to their ability of molecular self-assembly1-3 and have been widely used as nanotemplates for photonic crystals, high-density storage media, and nanoparticles. 4 It has been well-established theoretically5-8 and verified experimentally2, 9-11 that the size of the repeating structure of a block copolymer is expressed by molecular parameters involving conformational parameters. The long period (D) of the mesophase in a diblock copolymer is given as the scaling form of D∼ aN1/2Ψ (χN), where a is the statistical segment length, N is the total number of the statistical segment, χ is the Flory-Huggins interaction parameter between segments, and the scaling function Ψ (y) has the limiting values: Ψ (y)∼ 1 for y f 0 (ie, weak segregation limit (WSL)) and Ψ (y)∼ y1/6 for y f∞(ie, strong segregation limit (SSL)). Changing the molecular …