Wetting Characteristics of Laser-Ablated Hierarchical Textures Replicated by Micro Injection Molding

Area of Science:

• Materials Science
• Surface Engineering
• Fluid Dynamics

Background:

• Surface texturing is crucial for functionalizing plastic parts, particularly for controlling fluid interactions in applications like microfluidics and medical devices.
• Hierarchical surface structures offer advanced control over wetting properties.

Purpose of the Study:

• To investigate the fabrication of hierarchical textures on steel molds using femtosecond laser ablation.
• To analyze the replication of these textures onto plastic parts via injection molding.
• To evaluate the impact of different hierarchical geometries on surface wetting behavior.

Main Methods:

• Femtosecond laser ablation was employed to generate micro- and nano-scale hierarchical textures on steel mold inserts.
• Micro-injection molding was used to replicate the textured surfaces onto polypropylene (PP) and poly(methyl methacrylate) (PMMA) parts.
• Static wetting behavior was measured and compared with Cassie-Baxter and Wenzel models.

Main Results:

• Hierarchical textures were successfully transferred from steel molds to PP and PMMA plastic parts.
• The wetting behavior of PP parts aligned with the Cassie-Baxter model predictions.
• PMMA parts exhibited a composite wetting state, showing characteristics of both Cassie-Baxter and Wenzel models.

Conclusions:

• Femtosecond laser ablation and injection molding provide a viable route for creating functionalized plastic surfaces with controlled wetting properties.
• The study highlights the correlation between hierarchical texture design, manufacturing replication fidelity, and resulting wetting characteristics.
• Understanding wetting behavior on replicated textures is essential for designing advanced plastic components for fluidic applications.