Solvent‐Responsive Shape Memory Porous Semicrystalline Thermoplastic Polyurethane

The work investigates solvent-responsive shape memory behavior in porous thermoplastic polyurethane (TPU). Porous TPU is prepared by salt-leaching, and its shape recovery is tested when exposed to ethyl acetate (EA). The authors report that EA increases the mobility of TPU’s amorphous chains, and that a step-like glass transition feature disappears in DSC measurements. They also find that partial dissolution of crystalline TPU contributes to shape recovery without obvious swelling. Using XRD, the amount of partially dissolved crystalline material is shown to increase with immersion time, which improves the shape recovery ratio. Despite the much higher specific surface area from the porous structure, the recovery time is not reduced, and the interconnected pores help EA penetrate while the porous TPU maintains break strain and modulus comparable to dense TPU.