Grid-based dynamic electronic publication: A case study using combined experiment and simulation studies of crown ethers at the air/water interface.
Esther R Rousay, Hongchen Fu, Jamie M Robinson, Jeremy G Frey, Jonathan W Essex
School of Chemistry, University of Southampton,
Highfield, Southampton, SO17 1BJ, UK

Abstract The Publication@Source Paradigm and Challenges Body Molecular Dynamics Simulations Comparisons and Conclusions Acknowledgements Appendix:The TriScapeRDF browser References Glossary Search
Case Study Crown ether molecules at the water/air interface Introduction Benzo-15-Crown-5 UV Spectrum of Benzo-15-Crown-5 Surface Tension Measurements Second Harmonic Generation SHG Isotherm SHG Isotherm .2 Polarisation Dependence Polarisation Dependance Analysis The molecular hyperpolarisability and molecular orientation The molecular hyperpolarisability and molecular orientation .2 Analysis

Surface Tension Measurements

The surface tension measurements were made using the pressure sensor on a NIMA trough (Wilhelmy plate method) in a Teflon dish. Solutions were made with water purified using a Barnstead E-pure four-module purifier starting with pure water and adding aliquots of a 5 mM solution of benzo-15-crown-5. After each addition, it was necessary to leave the surface to equilibrate for about 5 minutes. The surface tension was recorded once the pressure sensor reading settled. The surface tension data were fitted using a cubic polynomial and the derivative obtained and the surface excess calculated using the Gibbs equation. The area per molecule (inverse of the surface excess) as a function of bulk concentration is shown in figure 4, along with the surface excess. The data are tending towards an area per molecule of about 88 ?2. This is slightly larger than the area of the flat molecule, which is estimated to be about 74 ?2 for a flat molecule using VMD.

Figure 4: Plot showing the surface excess (open diamonds), and the area occupied per molecule (filled diamonds), as derived from the surface tension measurements, over the bulk concentration range used. The figure is linked to the analysis used and then to the raw surface tension data

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