Large compound vesicles from amphiphilic block copolymer/rigid-rod conjugated polymer complexes

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Amphiphilic block copolymers like polystyrene-block-poly(acrylic acid) (PS-b-PAA) and polystyrene-block-poly(ethylene oxide) (PS-b-PEO) self-assemble into various morphologies in solution.
• Polyaniline (PANI) is a conducting polymer with potential applications in various fields.
• Understanding the self-assembly behavior of polymer complexes is crucial for designing novel materials.

Purpose of the Study:

• To investigate the morphology evolution of PS-b-PAA/PANI and PS-b-PEO/PANI complexes in aqueous solution.
• To explore the role of polyaniline content and formation kinetics on the self-assembled structures.
• To understand the underlying mechanisms driving morphology transformations.

Main Methods:

• Complexation of amphiphilic block copolymers with polyaniline in aqueous solution.
• Characterization of nanoparticle morphology using transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS).
• Controlled variation of polyaniline content and water addition methods during nanoparticle formation.

Main Results:

• Spherical micelles formed by pure block copolymers transformed into large compound vesicles with increasing PANI content.
• The interpolyelectrolyte complex between PAA and PANI was identified as a key factor in morphology changes.
• Different water addition methods led to the formation of nanoparticles with multiple geometries, indicating control over kinetic pathways.

Conclusions:

• Polyaniline content significantly influences the self-assembly morphology of PS-b-PAA and PS-b-PEO complexes.
• The formation of an interpolyelectrolyte complex is crucial for the observed morphology transitions.
• Kinetic control during nanoparticle formation offers a pathway to engineer diverse complex architectures.