Eur. Phys. J. E (2011) 34: 58
https://doi.org/10.1140/epje/i2011-11058-y

Regular Article

Time-resolved microfocused small-angle X-ray scattering investigation of the microfluidic concentration of charged nanoparticles

¹ UMR 5258 Rhodia-CNRS-Bordeaux 1, LOF, 178 avenue du Docteur Schweitzer, F-33608, Pessac cedex, France
² European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043, Grenoble, France

^* e-mail: jean-baptiste.salmon-exterieur@eu.rhodia.com

Received: 30 March 2011
Accepted: 18 May 2011
Published online: 10 June 2011

Abstract

We describe the concentration process of a dispersion of silica nanoparticles undergoing evaporation in a dedicated microfluidic device. Using microfocused small-angle X-ray scattering, we measure in time and space both the concentration field of the dispersion and its structure factor. We show that the electrostatic interactions affect the concentration rate by strongly enhancing the collective diffusion coefficient of the nanoparticle dispersion. En route towards high concentrations, the nanoparticles eventually undergo a liquid-solid phase transition in which we evidence crystallites of micron size.