Polymerisation-Induced Self-Assembly of Graft Copolymers

Area of Science:

• Polymer Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Controlled polymerization techniques like reversible addition-fragmentation chain transfer (RAFT) enable precise synthesis of complex polymer architectures.
• Graft copolymers, with their distinct polymer chains attached to a main backbone, offer unique self-assembly behaviors.
• Understanding polymer self-assembly is crucial for designing advanced materials with tailored properties.

Purpose of the Study:

• To investigate the polymerisation-induced self-assembly (PISA) of poly(lauryl methacrylate)-graft-poly(benzyl methacrylate) copolymers.
• To explore the influence of branched architecture on copolymer self-assembly during RAFT polymerization.
• To characterize the resulting morphologies and their transition with varying graft volume fractions.

Main Methods:

• Reversible Addition-Fragmentation chain Transfer (RAFT) grafting from polymerization.
• Electron microscopy (EM) for visualizing particle morphology.
• Small-angle X-ray scattering (SAXS) for structural analysis.
• Time-resolved SAXS to study dynamic morphological changes.

Main Results:

• Spherical particles formed due to graft phase separation, enabled by the branched architecture.
• Multicore micelles were observed, with morphologies transitioning from spheres to worms, vesicles, and inverted micelles as graft volume fraction increased.
• Time-resolved SAXS confirmed the formation of the inverted phase during polymerization.

Conclusions:

• The grafted architecture facilitates polymerisation-induced self-assembly into diverse and unusual morphologies.
• Controlling graft volume fraction allows for tunable micelle structures, from spheres to worms and vesicles.
• This approach provides novel strategies for manipulating polymer structure and material properties.