Magnetic ionic liquid-assisted alignment: morphology and orientation control in amorphous–amorphous diblock copolymer

Abstract This study proposes using magnetic ionic liquids, 1-butyl-3-methylimidazolium tetrachloroferrate (bmimFeCl₄), to achieve alignment in amorphous polymers without inherent magnetic anisotropy. Selective doping into the polar phase of polystyrene-polymethyl methacrylate diblock copolymer promotes magnetic responsiveness. Small-angle X-ray scattering analysis revealed that adding bmimFeCl₄ transitions microphase separation morphologies from cylindrical to lamellar due to volume fraction changes. Cross-polarization/magic-angle spinuing (CP/MAS) 13C nuclear magnetic resonance (NMR) spectroscopy confirmed bmimFeCl₄ localization in the polymethyl methacrylate phase. Thermal treatment within a magnetic field aligned interfaces parallel to the field direction, demonstrating control over morphology and orientation through magnetic ionic liquid doping.