The undesired long time for the self-assembly of block-copolymer (BCP) thin fi lms restricts their application as a template in lithography and other technologies. To shorten the assembly time, a facile but versatile strategy of solvent-vapor-induced rapid assembly into a uniform ordered morphology of polystyrene-block -poly(methyl methacrylate) (PS -b -PMMA) thin fi lm via prevacuumizing is reported. Factors such as the prevacuum pressure and the temperature during the solvent-vapor-annealing process are investigated for their effects on the assembly time. The morphologies are observed by transmission electronic microscopy (TEM) and the results indicate that the time for the assembly of PS-b -PMMA with a PS-cylinder-forming composition into a morphology of hexagonally arranged PS spheres in the fi lm, induced by the solvent vapor at a prevacuum pressure 0.02 atm, is only 4 min at 20 °C and shortens more to 1 min at 60 °C.

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Front Cover: The time frame for block copolymer selfassembly is becoming one of the most urgent items in exploring it as a template. The time needed for polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) thin film to assemble into a uniform ordered morphology by solvent vapor annealing is only 1 min at a prevacuum pressure 0.02 atm and 60 °C. Further details can be found in the article by Y. Gong, Y. Li, Y. He, L. Wang, H. Huang, and T. He* on page 1092.