Direct Observation of the Orientation of Urea Molecules at Charged Interfaces.
J Phys Chem Lett
; 12(44): 10823-10828, 2021 Nov 11.
Article
en En
| MEDLINE
| ID: mdl-34726406
ABSTRACT
Dissolving urea into water induces special solvation properties that play a crucial role in many biological processes. Here we probe the properties of urea molecules at charged aqueous interfaces using heterodyne-detected vibrational sum-frequency generation (HD-VSFG) spectroscopy. We find that at the neat water/air interface urea molecules do not yield a significant sum-frequency generation signal. However, upon the addition of ionic surfactants, we observe two vibrational bands at 1660 and 1590 cm-1 in the HD-VSFG spectrum, assigned to mixed bands of the CâO stretch and NH2 bend vibrations of urea. The orientation of the urea molecules depends on the sign of the charge localized at surface and closely follows the orientation of the neighboring water molecules. We demonstrate that urea is an excellent probe of the local electric field at aqueous interfaces.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Chem Lett
Año:
2021
Tipo del documento:
Article
País de afiliación:
Países Bajos