Silver nanoparticles stabilized by AOT and Tergitol NP-4 mixture: Influence of composition on electrophoretic concentration, properties of concentrated organosols and conductivity of films

Abstract

A comparative analysis of the main physico-chemical characteristics of silver nanoparticles produced in mixed reverse micelles of nonionic surfactant Tergitol NP-4 with addition of anionic AOT was carried out. The nanoparticles are shown to have a positive electrokinetic potential. The only exception is nanoparticles synthesized in Tergitol NP-4 reverse micelles without addition of AOT, which have a zero electrokinetic potential. An increase in AOT concentration in the mixture leads to a decrease in the size of particles produced and an increase in the electrokineticpotential. It was shown that silver nanoparticles with close to quantitative extraction rates can be concentrated by non-aqueous electrophoresis with AOT content in mixture equaled 5 mol% and more. For mixture with content of AOT more than 50 mol%, no concentration is observed for surfactants. In the systems with high content of Tergitol NP-4 an increase in the concentration of surfactants is observed compared to the starting organosol. A decrease in AOT concentration leads to a decrease in the stability of the nanoparticles that results in a reversible change in the surface plasmon resonance spectra of nanoparticles under drying and irreversible agglomeration of nanoparticles with a decrease in the surfactant concentration. The presence of reversible agglomeration of the nanoparticles is likely due to the strong negative effect of Tergitol NP-4 on the stability as well as the conductivity and adhesion of coatings produced by thermolysis of the nanoparticle concentrate.