Send to

Choose Destination
Langmuir. 2007 Oct 23;23(22):10995-9. Epub 2007 Sep 19.

ATR-FTIR observations of water structure in colloidal silica: implications for the hydration force mechanism.

Author information

Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, USA.


Attenuated total internal reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was used to probe the change in water structure in silica colloids as a function of particle density. The absorption index (k) spectra were calculated from the ATR spectra using the subtractive Kramers-Kronig transform in order to avoid the effects of the density-dependent refractive index on the raw spectra and allow direct comparison of the different chemical environments. Normalized difference spectra were obtained by subtracting the k spectrum of bulk water from those of the silica colloids. At low particle densities, these difference spectra reveal the presence of a strongly hydrogen-bonded hydration layer at the surface of the colloidal particles. At higher particle densities, the hydrogen-bonding network is increasingly disrupted. The results provide direct experimental evidence of hydrogen-bond breaking as the mechanism for the hydration force, which provides the extraordinary stability of colloidal silica.


Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center