Crystallization-modulated nanoporous polymeric materials with hierarchical patterned surfaces and 3D interpenetrated...

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Poly(oxymethylene)/poly(L-lactic acid) (POM/PLLA) blends are melt-miscible.
• Understanding their phase behavior during crystallization is key for developing advanced materials.

Purpose of the Study:

• To investigate the formation of cocontinuous phase structures in POM/PLLA blends during isothermal crystallization.
• To develop a method for creating nanoporous POM materials with controlled hierarchical structures.

Main Methods:

• Isothermal crystallization of POM/PLLA blends at various temperatures.
• Analysis of POM crystal morphology and phase separation.
• Selective extraction of PLLA to create nanoporous structures.

Main Results:

• POM crystallizes into banded spherulites, forming a continuous crystalline phase.
• Amorphous PLLA is expelled, creating a second continuous phase, leading to a cocontinuous structure.
• Extraction of PLLA yields nanoporous POM with hierarchical surfaces and 3D internal channels.
• POM crystal morphology and pore size are dependent on crystallization conditions.

Conclusions:

• A cocontinuous phase structure forms in POM/PLLA blends during crystallization.
• Nanoporous POM materials with tunable hierarchical structures can be fabricated by selective PLLA extraction.
• Crystallization conditions offer a route to modulate the pore size and surface patterns of the resulting materials.