Polylactide-Based Amphiphilic Block Copolymers: Crystallization-Induced Self-Assembly and Stereocomplexation.

Area of Science:

• Polymer Science
• Materials Science
• Colloid and Surface Chemistry

Background:

• Poly(ethylene glycol)-poly(lactide) block copolymers are amphiphilic polymers with potential applications in drug delivery and biomaterials.
• Understanding their self-assembly behavior in aqueous solutions is crucial for designing functional nanomaterials.

Purpose of the Study:

• To investigate the aqueous self-assembly of poly(ethylene glycol)-poly(lactide) block copolymers and their stereocomplexes.
• To elucidate the influence of polymer composition and stereochemistry on aggregate morphology.

Main Methods:

• Differential scanning calorimetry (DSC) to analyze thermal properties.
• Dynamic light scattering (DLS) to determine aggregate size and distribution.
• Transmission electron microscopy (TEM) for visualizing aggregate morphology.

Main Results:

• Block copolymers formed spherical micelles and worm-like aggregates, with worm formation increasing at lower lactide content.
• Worm-like aggregates resulted from polylactide crystallization, leading to micelle instability and epitaxial fusion.
• Stereocomplex aggregates exhibited different self-assembly, forming irregular clusters and pearl-necklace structures.

Conclusions:

• Aqueous self-assembly of PEG-PLA block copolymers is sensitive to hydrophobicity and polylactide crystallization.
• Stereocomplexation leads to distinct aggregate morphologies compared to non-stereocomplexed counterparts.
• These findings provide insights into designing tailored nanostructures for various applications.