Brookhaven National Lab
Monday, April 6, 2009
Wetting on the Nanoscale: How That Works?
Wetting phenomena are commonly observed in everyday life: rain drops rolling down a glass window and oil drops spreading on a frying pan are notable examples. Although the basic laws describing these macroscopic phenomena are relatively well understood, the picture changes significantly at the nanometer scale. At this small scale, microscopic effects – such as long range van der Waals interaction, thermal fluctuations of the liquid free surface, structural forces– become important leading to significant changes of the wetting and spreading behavior.
Research in this field is fostered by advancements in nano-patterning techniques which allow surfaces with well-defined chemical and or geometrical nanostructures to be routinely fabricated. These nanostructured surfaces can be used to confine liquids within extremely small volumes thereby performing complex biological or chemical analysis in a single miniature device (the “lab on a chip” concept).
In this talk, I will describe experimental studies of the wetting and spreading of liquids on nanostructured surfaces performed with atomic force microscopy and X-rays scattering techniques. The results of this research provide valuable insight into the wetting behavior at the nanoscale and a stringent test for available theories.