Fabricating Microstructures on Freeform Surfaces via Flexible Hydrogel Micromolds

Area of Science:

• Materials Science
• Nanotechnology
• Surface Engineering

Background:

• Fabricating microstructures on curved surfaces is crucial for engineering applications.
• Current methods often involve complex devices and procedures, posing a significant challenge.

Purpose of the Study:

• To present a novel, simplified approach for fabricating microstructures on curved surfaces.
• To utilize flexible microstructured hydrogels as molds for adaptable fabrication.

Main Methods:

• Microstructuring a photo-responsive hydrogel film using controlled ultraviolet illumination.
• Transferring the microstructured hydrogel to curved surfaces (including freeform) due to its low modulus.
• Using polydimethylsiloxane (PDMS) casting to create the final microstructured surfaces.

Main Results:

• Achieved high uniformity and surface smoothness (Ra ≈2.7 nm, Rq ≈4.1 nm) on microstructures.
• Demonstrated fabrication on large-area curved surfaces (≈4.5 cm x 6.5 cm).
• Confirmed good imaging performance of the fabricated microstructures.

Conclusions:

• The developed method simplifies microfabrication on complex curved surfaces.
• Flexible hydrogel molds offer adaptability to various surface topographies.
• This technique has potential for applications requiring precise microstructures on non-flat surfaces.