Phase Behavior of Tapered Diblock Copolymers from Self-Consistent Field Theory

Area of Science:

• Polymer Science
• Materials Science
• Soft Matter Physics

Background:

• Tapered diblock copolymers feature a gradient composition region instead of a sharp junction between polymer blocks.
• The 'normal' and 'inverse' configurations depend on the taper's attachment to the polymer blocks.

Purpose of the Study:

• To investigate the impact of taper length and direction on the phase diagrams and density profiles of tapered diblock copolymers.
• To compare the behavior of tapered systems with traditional diblock copolymers.

Main Methods:

• Utilized self-consistent field theory (SCFT) to model and analyze the copolymer systems.
• Examined changes in phase diagrams and polymer density profiles.

Main Results:

• Tapers shift the order-disorder transition to lower temperatures, with longer and inverse tapers having a more pronounced effect.
• Tapered systems do not behave identically to diblock copolymers even with adjusted effective temperatures.
• Normal tapering expands the bicontinuous gyroid phase, while inverse tapering contracts it due to distinct interfacial polymer arrangements.

Conclusions:

• Taper geometry is a critical factor controlling self-assembly in diblock copolymers.
• SCFT provides a robust framework for understanding the complex phase behavior induced by tapering.
• The findings offer insights for designing novel materials with tailored nanostructures.