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Home List of Titles Precision AFM measurements of dynamic interactions between deformable drops in aqueous surfactant and surfactant-free solutions
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/196098
- Precision AFM measurements of dynamic interactions between deformable drops in aqueous surfactant and surfactant-free solutions
- Lockie, Hannah J.; Manica, Rogerio; Stevens, Geoffrey W.; Grieser, Franz; Chan, Derek Y. C.; Dagastine, Raymond R.
- The atomic force microscope (AFM) has provided unprecedented opportunities to study velocity-dependent interactions between deformable drops and bubbles under a range of solution conditions. The challenge is to design an experimental system that enables accurate force spectroscopy of the interaction between deformable drops and thus the extraction of accurate quantitative information about the physically important force-separation relation. This step requires very precise control and knowledge of the interfacial properties of the interacting drops, the drive conditions of the force-sensing cantilever, the disposition of the interacting drops on the substrate and on the cantilever, and transducer calibrations of the instrument in order to quantify the effects of approach velocities and interfacial deformation. This article examines and quantifies in detail all experimental conditions that are necessary to facilitate accurate processing of dynamic force spectroscopy data from the AFM using the well-defined system of tetradecane drops in aqueous solutions under surfactant and surfactant-free conditions over a range of force magnitudes that has not been attained before. The ability of drops to deform and increase the effective area of interaction instead of decreasing the distance of closest approach when disjoining pressure exceeds the Laplace pressure means that the DLVO paradigm of colloidal stability as being determined by a balance of kinetic energy against the height of the primary maximum is no longer valid. The range of interfacially active species present in alkane-aqueous systems investigated provides insight into the applicability of the tangentially immobile boundary condition in colloidal interactions.
- Publication type
- Journal article
- Langmuir, Vol. 27, no. 6 (Feb 2011), pp. 2676-2685
- Publication year
- FOR Code(s)
- 0306 Physical Chemistry (Incl. Structural); 0903 Biomedical Engineering; 0904 Chemical Engineering
- Atomic force microscope; Bubbles; Colloidal interactions; Drops; Spectroscopy; Velocity-dependent interactions
- American Chemical Society
- Publisher URL
- Copyright © 2011 American Chemical Society.
- Additional information
- This work is supported by funding through the Australian Research Council and in part through the Particulate Fluids Processing Centre and the Australian Minerals Science Research Institute.
- Peer reviewed