A new and facile air-flow method was employed to prepare block copolymer membranes with different morphology.PS-b-PEO block copolymers were synthesized by atom transfer radical polymerization (ATRP).The molecular characteristics of the block copolymers were confirmed by 1H-NMR

FTIR spectroscopy and gel permeation chromatography (GPC).AFM and SEM were employed to characterize the surface morphology and inner structure of the films.Effects of molecular structure

air-flow velocity

air-flow temperature and substrate affinity on the membrane surface morphology and internal structure were studied.Vertically oriented microphase structure on the top surface of the membrane can be achieved when the PS mass fraction was between 83% and 85%

air-flow temperature was 50℃ and air-flow velocity was 4 m/s.When the liquid film was treated with an air speed outside the range of 3~5 m/s

no regular structure was observed.Similarly

when the air-flow temperature was too high or too low

no regular structure was observed.Substrates with different contact angles were prepared by chemical modification.Results showed that when the films were prepared on silicon substrates with contact angle less than 90 under appropriate air-flow condition

vertical orientation of cylinder nanochannels formed only in the regions at the top and bottom layers of the block copolymer films while irregular structure appeared in the middle part.