Shape‐Memory Polyurethane Nanocomposites with Single Layer or Bilayer Oleic Acid‐Coated Fe₃O₄ Nanoparticles

Abstract

The present study aimed at developing a shape‐memory material, whose shape can be changed “on demand” upon application of an external magnetic field. Shape‐memory nanocomposites were thus prepared from a commercially available thermoplastic polyurethane (PU) with a “switching temperature” of ≈40 °C and oleic acid (OA)‐coated Fe 3 O 4 nanoparticles (NPs). Two series of PU/Fe 3 O 4 nanocomposite films based on the shape‐memory PU and single layer or bilayer OA‐coated Fe 3 O 4 NPs were prepared by solution mixing followed by solvent casting. The thermal, mechanical, and shape‐memory properties of the nanocomposite films were studied and compared.