Thermally Induced Macromolecular Sequence Inversion in Triblock Copolymers and Terpolymers.

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Dynamic control over synthetic polymer sequences is a significant challenge.
• Current synthetic macromolecules lack the adaptability of natural biomacromolecules.
• Sequence control is crucial for tuning polymer properties and functions.

Purpose of the Study:

• To introduce a method for intra-macromolecular sequence inversion in polymers.
• To enable thermal reconfiguration of polymer sequences without changing composition or molecular weight.
• To demonstrate programmable polymer metamorphosis for stimuli-responsive materials.

Main Methods:

• Utilized a furan-maleimide-anthracene Diels-Alder system for reversible reactions.
• Synthesized symmetric (ABA) and asymmetric (ABC) triblock co/terpolymers using bifunctional initiators.
• Applied thermal treatment (120°C) to induce retro-Diels-Alder and subsequent cycloaddition for sequence inversion.

Main Results:

• Achieved sequence inversion from ABA to BAB and ABC to BAC architectures.
• Confirmed preservation of polymer chain integrity and molecular weight.
• Observed altered diffusion coefficients and distinct microphase-separated morphologies due to sequence changes.

Conclusions:

• The developed strategy enables programmable polymer metamorphosis.
• Sequence inversion significantly influences polymer properties like self-assembly and mechanical behavior.
• This opens new avenues for designing stimuli-responsive materials with tunable characteristics.