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Reversible Switching of Block Copolymer Nanopatterns by Orthogonal Electric Fields
Author(s) -
Liedel Clemens,
Lewin Christian,
Tsarkova Larisa,
Böker Alexander
Publication year - 2015
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201502259
Subject(s) - copolymer , materials science , electric field , nanotechnology , block (permutation group theory) , polymer , physics , composite material , geometry , mathematics , quantum mechanics
It is demonstrated that the orientation of striped patterns can be reversibly switched between two perpendicular in‐plane orientations upon exposure to electric fields. The results on thin films of symmetric polystyrene‐ block ‐poly(2‐vinyl pyridine) polymer in the intermediate segregation regime disclose two types of reorientation mechanisms from perpendicular to parallel relative to the electric field orientation. Domains orient via grain rotation and via formation of defects such as stretched undulations and temporal phase transitions. The contribution of additional fields to the structural evolution is also addressed to elucidate the generality of the observed phenomena. In particular solvent effects are considered. This study reveals the stabilization of the meta‐stable in‐plane oriented lamella due to sequential swelling and quenching of the film. Further, the reorientation behavior of lamella domains blended with selective nanoparticles is addressed, which affect the interfacial tensions of the blocks and hence introduce another internal field to the studied system. Switching the orientation of aligned block copolymer patterns between two orthogonal directions may open new applications of nanomaterials as switchable electric nanowires or optical gratings.