Ionic Strength and Thermal Dual-Responsive Bilayer Hollow Spherical Hydrogel Actuator

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Polymeric hydrogel actuators are promising intelligent materials for reversible shape change.
• Achieving 3D to 3D shape deformation in hydrogel actuators remains a significant challenge.

Purpose of the Study:

• To develop a novel bilayer hollow spherical hydrogel actuator.
• To achieve complex 3D to 3D shape deformations in hydrogel actuators using dual stimuli responsiveness.

Main Methods:

• Fabrication of a bilayer hydrogel actuator with a gelatin core.
• Formation of an ionic-strength-responsive alginate layer via alginate-Ca2+ crosslinks.
• Introduction of a thermo-responsive alginate-poly(2-(dimethylamino)ethyl methacrylate) (Alg-PDMAEMA) layer.

Main Results:

• A hollow hydrogel capsule was successfully obtained using a spherical gelatin core.
• The bilayer hydrogel actuator exhibited dual responsiveness to ionic strength and temperature changes.
• Complex 3D to 3D shape deformations were achieved upon external stimuli triggers.

Conclusions:

• The developed bilayer hollow spherical hydrogel actuator demonstrates effective 3D to 3D actuating behavior.
• This work provides new inspiration for designing advanced intelligent polymeric hydrogel actuators.