Polymerization-Induced Self-Assembly of Metallo-Polyelectrolyte Block Copolymers

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Developing stable, well-defined nanoparticles in aqueous media is crucial for various applications.
• Polymerization-induced self-assembly (PISA) offers a versatile route to nanoparticle synthesis.
• Cationic nanoparticles are of interest for drug delivery and biomedical applications.

Purpose of the Study:

• To synthesize cobaltocenium-containing polyelectrolyte block copolymer nanoparticles using PISA.
• To investigate the formation of stable, cationic nanoparticles in aqueous solution without added salts.
• To determine the influence of block copolymer composition and molecular weight on nanoparticle characteristics.

Main Methods:

• Aqueous dispersion RAFT polymerization was employed.
• A cationic macromolecular chain-transfer agent (macro-CTA) of poly(2-cobaltocenium amidoethyl methacrylate chloride) (PCoAEMACl) was used as the stabilizer.
• The core-forming block was poly(2-hydroxypropyl methacrylate) (PHPMA).

Main Results:

• Stable, cationic spherical nanoparticles with low dispersity were successfully prepared.
• The chain extension of the macro-CTA with HPMA was efficient and rapid.
• Nanoparticle size was significantly influenced by the degree of polymerization of both the PCoAEMACl stabilizer and the PHPMA core-forming block.
• The effects of solid content and charge density were also investigated.

Conclusions:

• Cobaltocenium-containing polyelectrolyte block copolymer nanoparticles can be effectively synthesized via aqueous dispersion PISA.
• The developed method yields stable cationic nanoparticles without the need for external salts.
• Control over nanoparticle size can be achieved by tuning the molecular weights of the constituent polymer blocks.