Enhanced Flexible Mold Lifetime for Roll-to-Roll Scaled-Up Manufacturing of Adhesive Complex Microstructures

Area of Science:

• Materials Science
• Manufacturing Engineering
• Surface Science

Background:

• Functional complex 3D patterned surfaces offer superior performance compared to smooth surfaces.
• Mass production of these micro-/nanostructured surfaces is hindered by challenges in mold repeatability, limiting commercialization.
• Existing roll-to-roll (R2R) manufacturing methods struggle with mold degradation over repeated cycles, especially with adhesive materials.

Purpose of the Study:

• To develop a strategy for significantly improving the repeatability of flexible silicone molds used in UV light curing based R2R systems.
• To overcome the limitations of mold degradation and enhance mold lifetime for mass production of micro-/nanostructured surfaces.
• To demonstrate the effectiveness of the proposed method for complex 3D undercut geometries and highly tacky materials.

Main Methods:

• Implementation of a two-step curing process for micropatterned flexible silicone molds.
• Utilizing UV light curing in a roll-to-roll (R2R) manufacturing system.
• Testing mold repeatability over numerous cycles against polyurethane acrylates (PUAs).

Main Results:

• The two-step curing process increased mold repeatability from tens to over 1000 cycles.
• This improvement was achieved despite complex 3D undercut geometries and the high tackiness of the microstructures.
• The enhanced mold lifetime facilitates scaled-up production of micro-/nanostructured functional surfaces.

Conclusions:

• The developed two-step curing strategy effectively resolves the mold repeatability issue in R2R manufacturing of micro-/nanostructured surfaces.
• This advancement enables the cost-effective, large-scale production of functional surfaces, including gecko-inspired adhesives.
• The enhanced flexible mold lifetime is crucial for the commercial viability of advanced micro-/nanopatterned products.