Modification of the fluctuation dynamics of ultra-thin wetting films

TL;DR

This study investigates how intermolecular forces influence the fluctuation dynamics of ultra-thin wetting films, revealing significant modifications at low frequencies and confirming theoretical models through experimental data.

Contribution

It demonstrates the impact of van der Waals forces on nanoscale film fluctuations and validates theoretical predictions with experimental results.

Findings

Intermolecular forces modify fluctuation dynamics at low frequencies.

Experimental data aligns with theoretical models including van der Waals forces.

Thermocapillary forces balance van der Waals forces in nanometer-thin films.

Abstract

We report on the effect of intermolecular forces on the fluctuations of supported liquid films. Using an optically-induced thermal gradient, we form nanometer-thin films of wetting liquids on glass substrates, where van der Waals forces are balanced by thermocapillary forces. We show that the fluctuation dynamics of the film interface is strongly modified by intermolecular forces at lower frequencies. Data spanning three frequency decades are in excellent agreement with theoretical predictions accounting for van der Waals forces. Our results emphasize the relevance of intermolecular forces on thermal fluctuations when fluids are confined at the nanoscale.