An evaluation of methods for contact angle measurement

Area of Science:

• Materials Science
• Surface Chemistry
• Physical Chemistry

Background:

• Surface wettability is crucial in materials science and surface chemistry.
• Accurate measurement of contact angles is essential for characterizing surface properties.
• Wilhelmy-balance tensiometry (WBT) is a common method, but comparisons with goniometric techniques are needed.

Purpose of the Study:

• To systematically compare Wilhelmy-balance tensiometry (WBT) with tilting-plate goniometry (TPG) and captive-drop goniometry (CDG).
• To evaluate the agreement of advancing and receding contact angles measured by these techniques on silane-treated glass surfaces.
• To establish the reliability of goniometric methods against a benchmark tensiometry technique.

Main Methods:

• Utilized three techniques: Wilhelmy-balance tensiometry (WBT), tilting-plate goniometry (TPG), and captive-drop goniometry (CDG).
• Employed a range of silane-treated glass surfaces with varying wetting characteristics.
• Performed systematic comparisons of advancing and receding contact angle measurements.

Main Results:

• Advancing contact angles measured by TPG and CDG showed statistical agreement with WBT measurements.
• Receding contact angles measured by both TPG and CDG were consistently higher than those obtained by WBT.
• The study highlights discrepancies in receding angle measurements between tensiometry and goniometry.

Conclusions:

• TPG and CDG are reliable for measuring advancing contact angles, aligning well with WBT.
• Significant differences in receding angles suggest caution when using TPG and CDG for such measurements compared to WBT.
• Further investigation into the discrepancies in receding angle measurements is warranted for precise surface characterization.