Physical properties of water near a gold surface: a nanorheological analysis.
Water at room temperature is not simply a medium for which uniform properties can always be assumed. Water close to solid hydrophobic or hydrophilic surfaces has elasticity, which is measured by monitoring the quartz crystal microbalance (QCM) resonant frequency and resistance. Small additions of salt are shown to modify this elasticity. Furthermore, near the hydrophobic QCM gold electrode, undersaturated aqueous NaCl solutions present a high concentration of ion pairs, which is confirmed by atomic force microscopy through force versus distance measurements.
Soares
David Mendez
DM
Laboratory of Nanostructures and Interfaces, Institute of Physics, University of Campinas-UNICAMP, C.P. 6165, 13083-970, Campinas, SP, Brazil. soares@ifi.unicamp.br
Tenan
Mário Alberto
MA
Gomide
Andreza Barbosa
AB
Gomes
Wyllerson Evaristo
WE