Nanosized Polyanilines Prepared with Ultrasound Oxidative Polymerization at Different Frequencies

Abstract

Polyaniline (PANi) nanoparticles were successfully prepared by applying ultrasound (US) irradiation during the oxidative polymerization of aniline in water. The US frequencies applied were 23, 43, and 141 kHz with varied exposure times. The formation of PANi nanoparticles was confirmed using laser diffraction particle size analysis (LDPA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of LDPA revealed that, when the US exposure lasted from 10 to 120 min, the nanosization of PANi was reduced at 141 kHz, whereas at a lower US frequency PANi formed aggregates with a larger size. The results of TEM indicated that the US frequency affected the aggregate size and particle size, meaning that a higher US frequency dispersed more efficiently nanosized particles.