3D printable and mechanically tunable hydrogels achieved through hydrophobic and ionic interactions.

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Thermal stiffening materials enhance dimensional stability and stiffness at elevated temperatures, crucial for aerospace and automotive applications.
• Existing materials often lack tunable properties or require complex fabrication methods.

Purpose of the Study:

• To develop temperature-triggered, modulus-tunable hydrogels with 3D printing capabilities.
• To investigate the mechanism of thermal stiffening and its reversibility.
• To explore the incorporation of additional functionalities like light-controllable modulus.

Main Methods:

• Formulation of hydrogel ink by combining Pluronic F-127 with charged polymers.
• Utilizing calcium ions for temperature-induced physical crosslinking.
• 3D printing of complex structures and characterization of thermal stiffening behavior.
• Incorporation of graphene oxide for photothermal property investigation.

Main Results:

• Successful preparation of hydrogel ink with high viscosity and fine resolution 3D printing capability.
• Demonstrated temperature-triggered thermal stiffening via calcium ion crosslinking without volume change.
• Confirmed the reversible and repeatable nature of the thermal stiffening effect.
• Achieved light-controllable modulus by incorporating graphene oxide.

Conclusions:

• The developed hydrogels exhibit tunable modulus and thermal stiffening properties, suitable for advanced manufacturing.
• The combination of Pluronic F-127 and charged polymers offers a versatile platform for creating functional materials.
• The incorporation of graphene oxide opens possibilities for photothermally responsive materials.