Stress-Free Two-Way Shape Memory Polymers with Dual-Crystalline Phase Based on Poly(Tetramethylene Ether Glycol) and...

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Two-way shape memory polymers (2W-SMPs) are smart materials capable of spontaneous, reversible deformation in response to stimuli.
• Precise control over 2W-SMP behavior and understanding their structure-property relationships are critical for advanced applications.

Purpose of the Study:

• To fabricate dual-crystalline phase crosslinked polymer networks for controlled two-way shape memory effects.
• To investigate the structure-property relationships governing the two-way shape memory behavior in these novel polymer networks.

Main Methods:

• Fabrication of dual-crystalline phase crosslinked polymer networks using poly(tetramethylene ether glycol) (PTMEG) and poly(ε-caprolactone) (PCL) via thiol-ene click reactions.
• Tuning network composition to achieve independent melting temperatures and enable two-way shape memory through inter-phase temperature differences.
• Investigating the influence of network composition, pre-tensile strain, and actuation temperature on shape memory properties.

Main Results:

• Successful fabrication of polymer networks with two distinct melting temperatures, enabling temperature-controlled two-way shape memory.
• PTMEG⁸-PCL² composition demonstrated optimal performance with an actuation strain of 24.25% and reversible strain up to 10.35% at 45°C and 15% pre-stretch.
• Elucidation of the two-way shape memory mechanism in dual-crystalline phase polymers.

Conclusions:

• The study successfully designed and fabricated dual-crystalline phase polymer networks exhibiting controlled two-way shape memory properties.
• The findings provide a pathway for designing semicrystalline networks with tunable two-way shape memory effects.
• The developed 2W-SMPs show significant potential for applications in soft robotics.