Morphological manipulation of ionic block copolymer micelles using an electric field

Area of Science:

• Polymer Science
• Materials Science
• Physical Chemistry

Background:

• Block copolymer micelles self-assemble into various morphologies in solution.
• Controlling micelle shape is crucial for advanced material applications.
• Electric fields are explored as external stimuli for morphological control.

Purpose of the Study:

• To investigate the electric-field-induced morphological transition of block copolymer micelles.
• To determine the minimum electric field required for this transition.
• To understand the reversibility of the shape change.

Main Methods:

• In situ small-angle X-ray scattering (SAXS) experiments.
• Electron microscopy (EM) and atomic force microscopy (AFM).
• Application of a direct current (dc) electric field.

Main Results:

• A sphere-to-cylinder transition was observed at a low electric field of 30 V/cm.
• Interconnected spheres formed transiently before cylinder formation.
• Cylindrical micelles reverted to spherical micelles upon removal of the electric field.

Conclusions:

• Block copolymer micelle morphology is highly tunable with low electric fields.
• This reversible transition offers potential for responsive materials.
• The findings open avenues for electric-field-controlled self-assembly.