College
College of Engineering and Polymer Science
Date of Last Revision
2026-04-28 12:32:49
Major
Chemical Engineering
Honors Course
CHEE 497-001
Number of Credits
3
Degree Name
Bachelor of Science
Date of Expected Graduation
Spring 2026
Abstract
Contact angle measurements are widely used to characterize surface wettability and determine changes in surface energy, yet the choice of measurement technique can significantly influence the results. This study compares the sessile drop and captive bubble methods for measuring contact angles of sodium dodecyl sulfate (SDS) solutions on carbon steel, stainless steel, and a hydrophobic wafer. Additionally, the time‑dependent wetting behavior of water, SDS, polysorbate 20 (commercial name Tween 20), and rhamnolipids on a hydrophobic wafer was evaluated over a five‑minute period. Results show that the sessile drop method consistently produced higher contact angles than the captive bubble method on metallic surfaces, with statistically significant differences at all SDS concentrations tested. These discrepancies arise from geometric and physical differences between the two methods. Time‑dependent measurements revealed that SDS, Tween 20, and rhamnolipids all reduced the contact angle on the hydrophobic wafer over time, with SDS showing the strongest concentration‑dependent effects and rhamnolipids exhibiting complex adsorption behavior. The captive bubble method showed minimal time dependence, indicating lower sensitivity to dynamic adsorption processes. Overall, the results highlight the importance of selecting an appropriate measurement technique based on surface type, surfactant chemistry, and whether dynamic or equilibrium behavior is of interest.
Research Sponsor
Dr. Bi-min Newby
First Reader
Dr. Lu-Kwang Ju
Second Reader
Dr. Scott Lillard
Honors Faculty Advisor
Dr. Bi-min Newby
Proprietary and/or Confidential Information
No
Community Engaged Scholarship
No
Recommended Citation
Darnell, Jack H., "Analysis of Sessile Drop and Captive Bubble Contact Angle Measurements on Metallic and Hydrophobic Surfaces" (2026). Williams Honors College, Honors Research Projects. 2120.
https://ideaexchange.uakron.edu/honors_research_projects/2120