Water-soluble polyphosphonate-based bottlebrush copolymers via aqueous ring-opening metathesis polymerization

Area of Science:

• Polymer Chemistry
• Macromolecular Science
• Materials Science

Background:

• Ring-opening metathesis polymerization (ROMP) is a powerful technique for creating complex polymer architectures.
• Polyphosphoesters (PPEs) offer biocompatibility and degradability, making them attractive for biomedical uses.
• Developing water-soluble and degradable bottlebrush polymers is crucial for advanced drug delivery and biomaterials.

Purpose of the Study:

• To synthesize water-soluble and degradable bottlebrush polymers based on polyphosphoesters (PPEs) via ROMP.
• To develop a general protocol for creating PPE-based bottlebrush polymers and block copolymers in aqueous media.
• To evaluate the biocompatibility and degradability of the synthesized polymers for potential biomedical applications.

Main Methods:

• Synthesis of PPE-macromonomers via organocatalytic anionic ring-opening polymerization.
• Utilizing N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide as an initiator and DBU as a catalyst.
• Subsequent ROMP of macromonomers using a Grubbs 3rd-generation catalyst in dioxane or aqueous conditions.
• Two-step protocol for synthesizing double hydrophilic diblock bottlebrush copolymers in water at neutral pH.

Main Results:

• Well-defined norbornene-based PPE macromonomers with controlled molecular weights and narrow dispersity were synthesized.
• ROMP successfully produced well-defined, water-soluble bottlebrush PPEs and diblock copolymers in aqueous conditions.
• Degradation studies confirmed the breakdown of PPE side chains into low molecular weight products.

Conclusions:

• A versatile and general protocol combining PPEs with ROMP enables the synthesis of advanced bottlebrush polymers in water.
• The synthesized polymers exhibit water solubility, degradability, and biocompatibility, suitable for biomedical applications.
• This approach offers a promising pathway for developing novel drug carriers and viscosity modifiers.