Studies of the Roughness of Films Based on Organosols of Silver Nanoparticles by Determining Contact Angles

Abstract

In the present work, we have proposed a method for estimating the roughness coefficient of films based on organosols of silver nanoparticles under conditions of homogeneous and heterogeneous wetting using the method for determining contact angles. Concentrated organosols of silver nanoparticles stabilized with a nonionic surfactant sorbitan monooleate have been used as initial systems. Films based on sols of silver nanoparticles were prepared by the Doctor Blade method followed by thermolysis (473–673 K for 2 h). All the samples were hydrophilic and had a complex, rough, and chemically inhomogeneous surface that could not be studied using the traditional wetting theory. Modification of the surface of the samples, as well as the smooth initial substrate, by deposition of gold nanoparticles of a size of 10 nm by ion sputtering have allowed us to prepare chemically homogeneous surfaces from the same material. Studies of the wettability of finite systems have allowed us to calculate their roughness coefficients. The parameter values ranged from 1.08 to 2.83 depending on the thermolysis temperature.