1. A Simple Approach for Local Contact Angle Determination on a Heterogeneous Surface
- Author
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Mengying Zhang, Xiang Wang, Shunbo Li, Weijia Wen, and Jinbo Wu
- Subjects
Surface (mathematics) ,SIMPLE (dark matter experiment) ,Chemistry ,Tension (physics) ,Analytical chemistry ,Surfaces and Interfaces ,Condensed Matter Physics ,Fluorescence ,law.invention ,Contact angle ,Rhodamine ,chemistry.chemical_compound ,Confocal microscopy ,law ,Electrochemistry ,General Materials Science ,Spectroscopy ,Line (formation) - Abstract
We report a simple approach for measuring the local contact angle of liquids on a heterogeneous surface consisting of intersected hydrophobic and hydrophilic patch arrays, specifically by employing confocal microscopy and the addition of a very low concentration of Rhodamine-B (RB) (2 × 10(-7) mol/L). Interestingly, RB at that concentration was found to be aggregated at the air-liquid and solid (hydrophobic patch only)-liquid interfaces, which helps us to distinguish the liquid and solid interfaces as well as hydrophobic and hydrophilic patches by their corresponding fluorescent intensities. From the measured local contact angles, the line tension can be easily derived and the value is found to be (-2.06-1.53) × 10(-6) J/m.
- Published
- 2011
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