We develop a non-lithographic method for fabricating ordered micro/nanostructures of polymer thin films based on controlled dewetting of the films on topographically pre-patterned substrates with a large area. An ordered nanopattern of polystyrene (PS) is accomplished by thermal treatment of a thin PS film above its T g spin coated on a topographically patterned substrate. We investigate the influence of pattern geometry on the final morphology of the dewetted polymer films using both mesa and indent patterned substrates. The controlled dewetting, initiated preferentially at the edges of individual pre-patterned mesas, in particular gives rise to spherical cap domains located at the center of the mesas. The domains are much smaller than the individual mesas as a consequence of the significant pattern reduction to nearly 300%. The arrays of 70 nm PS nano-sphere caps are obtained from arrays of 200 nm square pre-patterned mesas. Our method is also applicable for other polymers such as a poly(4-vinyl pyridine) (P4VP) containing Rhodamine 6G (Rh6G) dye on a pre-patterned PS substrate and successfully produced highly fluorescent stable nanopatterned films.

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Confining surface‐pinned micelles consisting of a block copolymer onto a topographically patterned substrate is demonstrated (see figure) with a novel approach to control both the local as well as global structural symmetry and periodicity of the self‐assembled block copolymer. No surface micelles are confined into the dents at the position of 1a. The surface micelles formed with bimodal size distribution are assembled into two different tetragonal symmetries indicated by the solid and dotted lines, respectively.

We have investigated the formation of as-cast thin films of a poly(styrene-block-4-hydroxystyrene) (PS-b-PHOST) copolymer spin-coated directly on topographic prepattern substrates. Either wetting or dewetting of a polymer thin film on the elevated regions occurs in the nonequilibrium state during spin-coating with solvent vapor saturated and strongly depends on the dimensions of the prepatterns. The ratio of periodic unit area to elevated one of a prepattern (β value) is found as one of the most important factors for wettability of a thin film. The dewetting of a thin film, guided by the edges of either elevated individual periodic lines or mesas, took place with self-assembled block copolymer nanostructure when the β value was greater than a critical value of ∼4 in our system.