A simple method for measuring the superhydrophobic contact angle with high accuracy.

Area of Science:

• Surface Science
• Materials Science
• Physics

Background:

• Contact angle (theta) measurement is crucial for understanding surface wettability.
• Traditional sessile-drop methods using tangent lines face challenges with smooth surfaces and substrate tilting, leading to baseline errors.
• These errors are amplified on superhydrophobic surfaces, impacting measurement accuracy.

Purpose of the Study:

• To propose a modified selected-plane method for accurate contact angle measurement.
• To overcome limitations of existing methods, especially for superhydrophobic surfaces.
• To provide a user-friendly program for theta measurement.

Main Methods:

• A modified selected-plane approach using four key data points: droplet apex, height, and two interfacial loci.
• Avoids the need to identify the precise contact point, unlike tangent-line methods.
• Eliminates the complex edge-fitting required by sessile-drop-fitting methods.

Main Results:

• The proposed method demonstrates high accuracy in contact angle (theta) measurement.
• It significantly improves upon classical selected-plane and sessile-drop-tangent techniques.
• The deviation from the sessile-drop-fitting method was less than three degrees.

Conclusions:

• The modified selected-plane method offers a robust and accurate alternative for contact angle measurement.
• It is particularly advantageous for characterizing superhydrophobic surfaces.
• The developed method simplifies measurement while enhancing precision.