Surface Forces and Rheology of Titanium Dioxide in the Presence of Dicarboxylic Acids: From Molecular Interactions to Yield Stress
Autor: | Vincent S. J. Craig, Yee-Kwong Leong, E-Jen Teh |
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Rok vydání: | 2017 |
Předmět: |
Fumaric acid
Molecular interactions Maleic acid Surface force 02 engineering and technology Surfaces and Interfaces Adhesion 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Rheology Chemical engineering Titanium dioxide Electrochemistry Organic chemistry General Materials Science 0210 nano-technology Spectroscopy Cis–trans isomerism |
Zdroj: | Langmuir. 33:1496-1506 |
ISSN: | 1520-5827 0743-7463 |
Popis: | The surface forces and yield stress of titanium dioxide were measured in the presence of dicarboxylic acids in order to understand the molecular basis for the observed rheological response. The yield stress was measured using the static vane technique, and the surface forces were characterized using an atomic force microscope. The trans and cis isomers of butenedioic acid (fumaric and maleic acids, respectively) were chosen as the relative orientation of the carboxylic groups differs substantially. This enables us to test the hypothesis that an increase in adhesion leads to an increase in yield stress as a consequence of the dicarboxylic acids participating in highly directed bridging. Unlike fumaric acid, maleic acid caused a yield stress reduction in the titanium dioxide suspensions. Surface force measurements between approaching surfaces found that at low pH, fumaric and maleic acids did not induce any additional attraction between the titanium dioxide surfaces. However, significant differences in adhesion were observed, which can be explained in terms of the configuration of the acids at the surface. The observations are consistent with highly directed bridging in the presence of fumaric acid but not in the presence of maleic acid due to the molecular architecture of the dicarboxylic acids. |
Databáze: | OpenAIRE |
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