Highly Oriented and Ordered Arrays from Block Copolymers via Solvent Evaporation

A simple process of solvent evaporation is shown to produce highly ordered arrays of cylindrical microdomains in block copolymers with long‐range lateral order (see Figure). Solvent evaporation in thin films is unidirectional, producing a self‐assembly directed normal to the film surface, akin to a zone refinement. Further control over the size and separation distance of the domains can be achieved with cosolvents.