Ultrasonic properties in Au nanoparticles reinforced PVA solution

Abstract

A polymer colloidal solution with dispersed nanoparticles of gold metal has been developed using a novel chemical reaction between Au3+ cations and polymer molecules of reactive surfaces of polyvinyl alcohol (PVA). Average size of Au particles could be varied in the range of 4–10 nm by conducting the reaction at an elevated temperature of 50–70°C. Colloidal solutions at representative concentrations of 0·1–1·0 wt-%Au contents in the primary solutions are used to study the modified ultrasonic attenuation and ultrasonic velocity in PVA polymer molecules on incorporating the Au particles using pulse echo technique. A characteristic minimum in velocity and maximum in attenuation are observed at the same temperature. The results demonstrate that the primary reaction during the Au–PVA colloidal formation occurs in divided groups in small micelles. The Au particles are encapsulated in PVA polymer molecules. The results are analyzed and discussed in correlation with the optical and electrical properties.