Nanometer-scale surface patterns with long-range order created by crystallization of diblock copolymers

We report experimental observations on the ordered surface patterns resulti ng from the crystallization of annealed thin films of microphase-separated low-molecular-weight hydrogenated poly(butadiene-b-ethyleneoxide) diblock c opolymers. For crystal growth rates higher than about 1 nm/sec the resultin g orientation of the crystalline lamellae was perpendicular to the substrat e. Alignment of these lamellae on large length scales was found when crysta llization occurred at boundaries crested by a dewetting process.