Behaviour for Nanoparticle Synthesis During and After Microwave Irradiation -In-situ Observation by Dynamic Light Scattering Method-

Abstract

There are some problems like aggregation and bubble formation around nuclei in process of microwave-assisted nanoparticle synthesis. To solve them, anti-solvent addition was tried in this study, and the mechanism of fine particle was considered through the results of size profiles obtained from in-situ observation tool of dynamic light scattering equipped with microwave reactor. First, when iron (III) sulphate (Fe₂(SO₄)₃) solution is heated up by microwave, larger particle and larger bubble during the irradiation, and aggregation after the irradiation were observed. Secondly, by the addition of ethylene glycol as an anti-solvent, bubble and particle sizes became smaller. This is because microwave absorbance energy is distributed to more particles in the solution with higher suspension density, which are promoted by the quick thermal response and the anti-solvent effect, the energy per one particle became lower. At the same time, the anti-solvent addition could prevent aggregation of particle due to the decrease in ionic strength of aqueous solution with anti-solvent.