Orthogonal Radical and Cationic Single-Unit Monomer Insertions for Engineering Polymer Architectures.

Area of Science:

• Polymer Chemistry
• Macromolecular Science
• Organic Synthesis

Background:

• Living/controlled polymerization techniques enable precise polymer synthesis.
• Functionalizing polymers with complex architectures requires incorporating diverse monomer types.
• Existing single-unit monomer insertion (SUMI) methods often lack compatibility with different polymerization mechanisms.

Purpose of the Study:

• To develop an orthogonal single-unit monomer insertion (SUMI) technique.
• To enable the simultaneous incorporation of radically and cationically polymerizable monomers into complex polymer structures.
• To achieve compatibility between radical and cationic SUMI processes for versatile polymer synthesis.

Main Methods:

• Developed an orthogonal SUMI technique by combining radical and cationic SUMI approaches.
• Optimized monomer and chain transfer agent pairs and reaction conditions for one-pot synthesis.
• Integrated radical and cationic reversible addition-fragmentation chain transfer (RAFT) polymerization.

Main Results:

• Successfully executed radical and cationic SUMI processes in one pot without mutual interference.
• Synthesized diblock, triblock, and star polymers incorporating both cationically and radically polymerizable monomers.
• Created side-chain sequence-controlled polymer brushes via a mixed radical and cation mechanism in RAFT step-growth polymerization.

Conclusions:

• The orthogonal SUMI technique offers a versatile platform for synthesizing complex polymers.
• This method overcomes limitations of integrating diverse polymerization mechanisms.
• Enables advanced polymer architectures, including sequence-controlled polymer brushes.