Capillary formation of alcohol meniscus and dynamic measurement of its viscoelasticity*

We present a novel method for producing a nanometric meniscus of several alcohols, such as acetone, ethanol and methanol, and the in situ measurement of their mechanical properties such as the viscoelasticity. The atomic force microscope based on the quartz tuning-fork sensor is employed to form and manipulate the nanometric alcohol meniscus, and the theoretical tool of amplitude-modulation atomic force microscopy is used to obtain the elasticity, viscosity and dissipation energy of it. With high vertical resolution less than 0.1 nm and high force sensitivity of 0.01 N/m, this tool facilitates the stable formation and manipulation of a nano-alcohol cluster (~10^4 molecules) in air without ‘jump-to-contact’ instability, as well as quantitative measurements of its physico-chemical properties.