Polydimethylsiloxane-assisted alignment transition from perpendicular to parallel of cylindrical microdomains in block copolymer films

The orientation transition from perpendicular to parallel alignment of PEO cylindrical microdomains within PEO-b-PMA(Az) films has been demonstrated via introducing a small amount of polydimethylsiloxane (PDMS) into block copolymers (BCPs). The introduced PDMS can change the surface energy difference of the two blocks and induce a soft shearing force during the annealing process, which affects the alignment of PEO cylindrical domains synergically. With this understanding, the PDMS-assisted method can possibly be generalized to align a wide variety of other BCPs. The BCP films with controllable alignment can be used as lithographic nanotemplates to prepare nanowire arrays, which have enormous potential application in the field of integrated circuits.