Grain Rotation in Ion-Complexed Symmetric Diblock Copolymer Thin Films under an Electric Field

In symmetric polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer thin films, lithium−PMMA complexes were formed with the addition of lithium chloride (LiCl), significantly increasing both χ and dielectric constant. These led to a transition in the kinetic pathway of the orientation of lamellar microdomains under an applied electric field from a disruption and re-formation of the microdomains to a grain rotation mediated by movement of defects. By controlling the number of lithium−PMMA complexes, the microdomain alignment is possibly regulated in PS-b-PMMA copolymer thin films.