Controlling the wettability of hierarchically structured thermoplastics

Area of Science:

• Materials Science
• Surface Science
• Polymer Science

Background:

• Surface properties are critical for material performance, influencing wetting, biomolecule interactions, and adhesion.
• Tailoring surface wettability is essential for diverse applications, from biomedical devices to microfluidics.

Purpose of the Study:

• To develop and characterize surfaces with controlled superhydrophobic and superhydrophilic properties on cyclic olefin polymers and copolymers (COPs/COCs).
• To investigate the combined effects of microscale structuring and nanoscale plasma etching on surface wettability and stability.

Main Methods:

• Hot embossing was used to create microscale features on COPs/COCs.
• Plasma activation with O(2), CF(4), or a mixture of both gases was employed for surface functionalization and nanoscale etching.
• Atomic force microscopy (AFM), contact angle measurements, and X-ray photoelectron spectroscopy (XPS) were utilized for characterization.

Main Results:

• Microstructures significantly enhanced hydrophobic properties.
• Plasma etching introduced nanoscale roughness and chemical modification, creating either superhydrophilic or superhydrophobic surfaces (contact angle >150°).
• The developed surfaces demonstrated excellent long-term stability (>6 months) in their superhydrophobic/superhydrophilic states.

Conclusions:

• Combining microscale features with plasma-etched nanoscale roughness and chemical modification provides effective control over surface wettability.
• The developed COPs/COCs surfaces offer tunable and stable superhydrophobic or superhydrophilic characteristics for advanced material design.