A novel low-voltage responsive NIPAAm/CNTs/Fe(phen)3 double network shape-changing hydrogel with a balance between mechanical properties and deformation ability

Abstract

The trade-off of electro-induced shape-changing hydrogels (EISCHs) between mechanical properties and deformation ability limited its further applications. In this work, the double network technique of reinforcing nondeformable hydrogels’ mechanical properties was introduced into EISCHs, and the NIPAAm/CNTs/Fe(phen)3 double network low-voltage-induced shape-changing hydrogel (DN) was synthesized. The experimental results indicated that the DN gained the balance between mechanical properties and deformation ability compared to the NIPAAm-Fe(phen)3 single network and NIPAAm-Fe(phen)3-CNTs nanocomposite single network hydrogels. The DN was found to have the ability to undergo swelling and shrinking as a result of the transition between Fe(phen)3 network iron (Ⅱ) and iron (Ⅲ) states under low-voltage stimulation. The hydrogen bonding and physical entanglement structure between CNTs and polymer chain segments, and physical entanglements between different network, which enable effective energy dissipation. Meanwhile, the special double network structure enabled the hydrogel could decrease the resistance to deformation stress by the slide between two networks.

Keywords

• Low-voltage response
• Double network
• Electro-induced shape-changing hydrogels
• Deformation ability
• Mechanical properties