(393i) Effects of the Nanoscale in Interfaces Solid-Gas-Liquid

It is well established that reducing the sizes of particles leads to a dramatic increase in the portion of surface/interface atoms. Since the properties of a solid are essentially controlled by related surface/interface energies such effects affect many physicochemical properties that can be observed at the macroscale. Although such effects are believed to be present every time that nanoparticles are added to a given system, particularly at interfaces where gas-solid-liquid coexist; there are few experimental experiences for the expected phenomena that we are ought to “see” at the macroscale.

This work aims to analyze the influence of the nanoscale properties (e.g particle size) in thermodynamics and physicochemical interactions of substances, in a mixture that contains nanoparticles, through the study of the dynamics of a falling drop and the observation of changes during the drop impact by introducing nanoparticles of known size. The evolution of the drops has been recorded by a high-speed camera and image analysis techniques are used for obtaining quantitative data from the details of drop impact, initial drop deformation and further spreading (a phenomena which is driven mainly by surface tension) and where nanoscale effects will manifest more evidently.

Recent theoretical studies predict that solid–vapor interface energy, liquid–vapor interface energy, solid–liquid interface energy, and solid–solid interface energy of nanoparticles and thin films fall as the diameter or thickness decreases to several nanometers while the solid–vapor interface energy ratio is size-independent and equals that of the bulk [1].  Some results and discussion will be provided regarding the validity of these theoretical predictions.

Keywords:Nanoscale effects, Nanoparticles, surface energy.

References:

[1] Q. Jiang  and H.M. Lu Size dependent interface energy and its applications. Surface Science Reports 63 (2008) 427–464