Under mixed water and methanol vapor atmospheres, a poly(9,9-dihexylfluorene)/CH2Cl2 solution self-assembles to form various nano/microstructures, such as porous films, spherical segments and microspheres. The water droplet template and the polymer precipitation by methanol were the driving forces that fabricated the patterns. Porous films with different pore sizes were obtained in CS2 solution by altering the mixed vapor atmosphere. Changes in the spreading coefficient and solvent polarity led to the formation of different morphologies. The introduction of miscible solvent vapors in aqueous atmospheres is a facile way to design and fabricate polymeric nano/microstructures. (C) 2014 Elsevier Ltd. All rights reserved.