Electric field influenced alignment of symmetrical lamellar diblock copolymers confined within polar discs.

Abstract

Controlling the self-assembly of nanoscale morphologies by applying a surface field to diblock copolymers leads to potential applications in optics, sensors, nanolithography templates, and high-density media. In this paper, we predict the alignment behaviour of symmetric diblock copolymers confined in annular discs in response to an applied electric field. Investigations have focused on new trends in lamellar patterning that are influenced by variations in microphase separation, electric field strength, pore size, and disc inner radius. The cell dynamics simulation model is a discrete version of the time-dependent Ginzburg-Landau (Cahn-Hilliard-Cook) equation that captures the dynamic evolution of novel morphologies in curves, expressed in polar coordinates. The competition between electric-field-driven ordering and geometric confinement offers insight into controlling alignment in coherent lamellar morphology under local confinement. It is demonstrated that under confined domains, the electric field aligns the lamellar patterns into concentric and radial orientations associated with confinement domains. The competition between electric-field-driven ordering and geometric confinement provides insight into controlling alignment in coherent lamellar morphology under local confinement. The weak electric field is insufficient to overcome the frustration caused by thermal fluctuations and curvature. Excessively strong electric fields also drive the system into kinetically trapped metastable states with persistent defects. An intermediate electric field strength provides an optimal balance between defect relaxation and electrostatic driving, resulting in a defect-free, aligned lamellar morphology.