Design of Linear Block Copolymers and ABC Star Terpolymers That Produce Two Length Scales at Phase Separation

Area of Science:

• Materials Science
• Polymer Chemistry
• Condensed Matter Physics

Background:

• Quasicrystals exhibit long-range order without traditional crystal periodicity.
• Their stability in soft matter is linked to two specific length scales in a 1.93 ratio.
• Designing polymers to achieve these scales is crucial for controlled synthesis.

Purpose of the Study:

• To propose design criteria for block copolymers that promote quasicrystal formation.
• To identify polymer architectures yielding specific length scales at phase separation.
• To explore synthesis strategies for creating quasicrystal-forming block copolymers.

Main Methods:

• Utilizing the Random Phase Approximation (RPA) for theoretical calculations.
• Modeling linear (A_L B A_S B) and star (ABC) terpolymer melts.
• Analyzing parameter windows for achieving the critical 1.93 length scale ratio.

Main Results:

• Identified specific parameter windows for both linear and star block copolymers.
• Demonstrated the emergence of the desired 1.93 length scale ratio in modeled systems.
• Proposed two simplified polymer models (monodisperse melt and random reaction mixture) conducive to synthesis.

Conclusions:

• Block copolymer design can controllably yield the length scales required for quasicrystal formation.
• The proposed models offer viable pathways for synthesizing soft matter quasicrystals.
• This work provides a foundation for the rational design of novel quasicrystalline materials.