Crystallization-driven formation poly (l-lactic acid)/poly (d-lactic acid)-polyethylene glycol-poly (l-lactic acid)...

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Engineering

Background:

• Hydrophobicity is crucial for various applications, often achieved by controlling surface microstructures.
• Nonsolvent-induced phase separation (NIPS) is a method for creating complex surface morphologies.

Purpose of the Study:

• To prepare a surface with tunable microsphere structures for enhanced hydrophobicity.
• To investigate the self-assembly behavior of amphiphilic block copolymers in phase separation.
• To explore the role of stereocomplex crystalline formation in surface morphology development.

Main Methods:

• Synthesis of Poly(D-Lactic acid)-block-poly(ethylene glycol)-block-poly(D-Lactic acid) (PDLA-PEG-PDLA) triblock copolymers via ring-opening polymerization.
• Fabrication of poly(L-lactic acid) (PLLA)/PDLA-PEG-PDLA membranes using nonsolvent-induced self-assembly (NIPS).
• Tuning of copolymer content and PEG chain length to control microsphere characteristics.

Main Results:

• Microsphere structures with adjustable quantity, diameter, and surface roughness were successfully fabricated.
• The amphiphilic block copolymers self-assembled into core-shell micellar structures during phase separation.
• Stereocomplex crystalline formation, facilitated by PEG segments, influenced the phase separation transition.
• The resulting membranes exhibited excellent hydrophobicity and controlled release of oil-soluble substances.

Conclusions:

• NIPS is an effective method for creating tunable hydrophobic microsphere surfaces.
• The self-assembly of PDLA-PEG-PDLA copolymers and stereocomplex formation are key to achieving desired surface morphologies.
• The developed membranes show potential for applications requiring controlled release of oil-soluble substances.