4D Printing of a Light-Driven Soft Actuator with Programmed Printing Density

Area of Science:

• Materials Science
• Additive Manufacturing
• Soft Robotics

Background:

• Four-dimensional (4D) printing merges 3D manufacturing with dynamic control for advanced bioinspired soft materials.
• Conventional methods struggle with low resolution, micro/nanostructure control, and rapid actuation for soft materials.

Purpose of the Study:

• To develop a high-resolution 4D printing approach for creating bioinspired soft actuators with programmed functionality.
• To overcome limitations in fabrication resolution and material response for complex soft actuators.

Main Methods:

• Utilized multiphoton lithography (MPL) for precise, pixel-by-pixel control of printing density in gels at the nanoscale.
• Synthesized a functional, thermoresponsive macrocrosslinker to enhance printing resolution.
• Incorporated gold nanorods (AuNRs) into a poly(N-isopropylacrylamide) (PNIPAm) matrix for photothermal actuation.

Main Results:

• Achieved high-resolution (hundreds of nanometers) printing density control in thermoresponsive gels.
• Demonstrated the fabrication of a 3D soft actuator with defined geometry and programmed printing density.
• Enabled fast, programmed actuation in nanocomposite soft actuators via light-mediated plasmonic heating of AuNRs.

Conclusions:

• MPL offers unprecedented control over soft material microstructures for 4D printing.
• The developed approach enables the creation of adaptive, bioinspired soft actuators with complex, rapid responses.
• Light-mediated manufacturing and manipulation are key to advancing 4D printing for adaptive soft materials.