Abstract
A robotic Wilhelmy balance (plate method) that automates data acquistion from a multiplicity of liquid samples is described. The design employed a commercial XYZ translation stage to locate a force transducer over any one of an XY array of liquid-sample positions. Z motion performed the immersion/withdrawal cycles involved in measurement of contact-angle hysteresis curves. Data files corresponding to the individual hysteresis curves were analyzed batch-mode by computer according to algorithms specifically developed for this task. Utility of the robotic balance as an extension of available surface-science analytical tools was demonstrated in four general wetting applications: (i) measurement of liquid-vapor interfacial tensions (γ(lv)) of water and organic fluids, (ii) determination of contact angles formed by these fluids on silane-treated glass and silicon-metal substrata, (iii) measurement of concentration-dependent γ(1v) for three surfactants and a protein (nonionic, Tween-80; anionic, Aerosol-OT; and cationic, cetyl dimethylethylammonium bromide; human serum albumin, HSA), and (iv) monitoring Tween-80 and HSA adsorption kinetics to a silane-treated glass slide. These studies verified that a robotic balance approach could provide accurate contact angle and interfacial tension measurements of both organic liquids and aqueous surfactant solutions.
Original language | English (US) |
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Pages (from-to) | 2470-2477 |
Number of pages | 8 |
Journal | Langmuir |
Volume | 9 |
Issue number | 9 |
DOIs | |
State | Published - 1993 |
All Science Journal Classification (ASJC) codes
- General Materials Science
- Condensed Matter Physics
- Surfaces and Interfaces
- Spectroscopy
- Electrochemistry