Impact of Replicated Biomimetic Microstructures on the Wettability of Injection-Molded Polymer Surfaces

Area of Science:

• Materials Science
• Surface Engineering
• Biomimetics

Background:

• Biomimetic surface design is crucial for controlling material wettability.
• Replication accuracy of natural structures under varying processing conditions needs further investigation.
• Understanding the interplay between processing parameters and replicated topology is key for functional surface design.

Purpose of the Study:

• To evaluate the influence of replicated natural structures on polymer part wettability.
• To systematically analyze the effect of melt temperature and packing pressure on microstructure replication.
• To explore the tuning of surface properties through topological design and processing parameters.

Main Methods:

• Micro-machining of hierarchical microstructures inspired by biomimetics.
• Molding of test samples from polypropylene (PP), acrylonitrile butadiene styrene (ABS), and polyamide 6.6 (PA 6.6).
• Contact angle (CA) measurements to assess wettability under varied temperature and pressure conditions.

Main Results:

• Surface wettability varied significantly with polymer type, melt temperature, and packing pressure.
• Hydrophilic reliefs achieved contact angles below 90° for all polymers, e.g., PP decreased from 98.7° to 82.4°.
• Hydrophobic reliefs yielded contact angles over 100°, with PP reaching 108.3° at specific conditions.
• Optimal processing parameters ensured accurate microstructure replication and preserved functional wettability.

Conclusions:

• Melt temperature and packing pressure critically influence the replication fidelity of biomimetic microstructures.
• Precise control over processing parameters allows for the tuning of surface wettability in polymer parts.
• This research demonstrates a pathway to engineer surface properties via biomimetic topological design and optimized manufacturing.