Multivalent cations-triggered rapid shape memory sodium carboxymethyl cellulose/polyacrylamide hydrogels with tunable...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Shape memory hydrogels are advanced materials with the ability to recover their original shape when subjected to a stimulus.
• Developing hydrogels with tunable mechanical properties and efficient shape recovery remains a key challenge in materials science.

Purpose of the Study:

• To synthesize novel multivalent cations-triggered shape memory hydrogels.
• To investigate the shape memory mechanism and mechanical properties of polyacrylamide/sodium carboxymethyl cellulose composite hydrogels.

Main Methods:

• A one-pot synthesis method was employed to create interpenetrating double network hydrogels.
• The temporary shape was fixed via complexation between sodium carboxymethyl cellulose (CMC) and various transition metal ions (Fe3+, Ag+, Al3+, Cu2+, Ni2+, Mg2+).
• Shape recovery was triggered by molecules or anions that disrupt the CMC-metal ion cross-links.

Main Results:

• The synthesized hydrogels exhibited excellent shape memory properties, with the CMC-Fe3+ hydrogel showing a shape fixity ratio of 95%.
• The hydrogels demonstrated tunable mechanical properties, adjustable by altering cross-linking densities.
• A variety of molecules and anions were found to effectively break the temporary cross-links, facilitating shape recovery.

Conclusions:

• The study successfully developed a novel class of multivalent cations-triggered shape memory hydrogels.
• The polyacrylamide/sodium carboxymethyl cellulose composite hydrogels offer tunable mechanical properties and efficient shape recovery.
• The presented strategy provides a new approach for constructing and utilizing biopolymer-based shape memory hydrogels.