Properties of confined and sheared rhodamine B films studied by SFA-FECO spectroscopy
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Updated: Jul 17, 2026

Real-time Monitoring of Ligand-receptor Interactions with Fluorescence Resonance Energy Transfer
Published on: August 20, 2012
Anna R Godfrey Alig1, Delphine Gourdon, Jacob Israelachvili
1Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
Abstract:
We have used a surface forces apparatus and multiple beam interferometry to measure the absorbance of thin films of rhodamine B in water/ethylene glycol solutions while applying and measuring normal and lateral (shear) forces. Both normal and shear forces induced changes in the absorption spectra indicating a change in molecular alignment, and rhodamine-rhodamine and rhodamine-surface interactions. We also measured differences in the absorbance spectra in different regions of the contact indicating, as expected, that the stresses are not uniform throughout the contact area. We also observed crystallization (solidification) parallel to the shearing direction.
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