Self-assembled carboxylic acid-functionalized carbon nanotubes grafting onto carbon fiber for significantly improving electrical actuation of shape memory polymers

This study presents an effective approach to significantly reduce the electrical resistivity of thermally responsive shape memory polymer (SMP) nanocomposites that show Joule heating triggered shape recovery. Carboxylic acid-functionalized carbon nanotubes (CNTs) self-assembled and grafted onto the carbon fibers, were used to enhance the reliability in bonding between the carbon fiber and the SMP via van der Waals and covalent crosslinking, respectively. It was found that the electrical properties of SMP nanocomposites have been improved by the synergistic effect of carboxylic acid-functionalized CNTs and carbon fibers. Furthermore, the electrically responsive recovery behavior and temperature distribution were monitored and characterized. Finally, the molecular structure and temperature dependent electrical behavior were studied, and verified the electro-activated recovery performance of the SMP nanocomposites.