Tunable Shape Memory Performances via Multilayer Assembly of Thermoplastic Polyurethane and Polycaprolactone

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Shape memory materials offer transformative applications in various fields.
• Conventional polymer blends often face limitations in achieving optimal shape memory performance.
• Multilayered structures present a novel approach to overcome these limitations.

Purpose of the Study:

• To fabricate and characterize multilayered shape memory materials using thermoplastic polyurethane (TPU) and polycaprolactone (PCL).
• To investigate the influence of layer number and material properties on shape memory behavior.
• To elucidate the underlying mechanisms governing shape-fixing and shape-recovery in these multilayer systems.

Main Methods:

• Layer-multiplying extrusion was employed to create alternating TPU/PCL multilayer structures.
• Shape-fixing and shape-recovery ratios were quantitatively assessed.
• Viscoelastic modeling was utilized to analyze energy transfer and interfacial effects.
• Variations in TPU hardness and PCL layer morphology were systematically studied.

Main Results:

• The fabricated multilayer structures exhibited a controlled co-continuous morphology with stable layer spaces.
• Increasing the number of layers significantly enhanced both shape-fixing and shape-recovery ratios compared to conventional blends.
• Interfacial shearing effects between TPU and PCL layers were crucial for maximizing the contribution of each component.
• Lowering TPU hardness and using a co-continuous TPU/PCL blend for PCL layers further improved shape memory performance.

Conclusions:

• Multilayer assembly is a highly effective strategy for developing advanced shape memory materials.
• The number of layers and component properties critically influence shape memory efficiency.
• Understanding interfacial mechanics provides insights for designing high-performance shape memory polymers.