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Fabrication of mesoscopic block copolymer regular structures by dewetting and phase separation

This paper describes the preparation of polymer patterns formed from dip coating a solid substrate in a dilute polymer solution, where the formation of extremely regular and organized structures of well-distanced ribbons and dots took place. The phenomenon was rationalized in terms of a combination of effects, such as thermocapillary flow (Marangoni effect), dewetting of liquid films and effects from the receding meniscus. The primary structures were ribbons, which are unstable due to Rayleigh instability and can split into arrays of ordered dots. Microphase separation of the block copolymer also played a significant role, which distinguishes this process from previously described ones, as it represents an additional tool for structural control. The thickness of the final nanostructures lies in the range of tens of nanometers, the same order of magnitude of the periodic repeating distance of the block copolymer microstructure. The ribbons width and the dot diameter vary from 200 to 600 nm.