Quantifying Surface Wetting Properties Using Droplet Probe Atomic Force Microscopy

Area of Science:

• Surface science
• Materials science
• Nanotechnology

Background:

• Surface wettability dictates functional properties like anti-fogging and anti-fouling.
• Contact angle measurements are standard for wettability but limited for microscale droplets and heterogeneity analysis.
• Macroscopic wetting properties are well-described, but microscale phenomena remain challenging.

Purpose of the Study:

• To develop a novel method for quantitatively measuring surface wettability at the microscale.
• To overcome the limitations of traditional contact angle measurements for small droplets and heterogeneous surfaces.
• To enable high-resolution mapping of surface properties relevant to fouling and functional performance.

Main Methods:

• Utilized atomic force microscopy (AFM) to measure interaction forces between a microdroplet and a surface.
• Achieved piconewton force resolution for quantitative interaction force measurements.
• Developed a technique for spatially mapping surface characteristics with micron resolution.

Main Results:

• Demonstrated the ability to quantitatively measure microdroplet-surface interaction forces.
• Successfully mapped topographical and chemical heterogeneities on surfaces with micron resolution.
• Provided a new tool for understanding microscale wetting phenomena.

Conclusions:

• The developed AFM technique offers a powerful alternative to contact angle measurements for microscale wettability.
• This method allows for detailed characterization of surface properties, crucial for anti-fouling and anti-fogging applications.
• Spatially resolved force measurements provide insights into factors influencing surface fouling and performance.