Microfluidique et diffusion de rayons X aux petits angles : des outils pour étudier les processus sol-gel

Microfluidics and small angle X-ray scattering for investigating sol-gel processes

¹ LOF, Unité mixte CNRS-Rhodia, 178 av. Schweitzer, 33608 Pessac, France
² ESRF, 6 rue Jules Horowitz, 38000 Grenoble, France

Auteur de correspondance : fanny.destremaut-exterieur@eu.rhodia.com

Abstract

X-ray scattering is a classical tool to probe soft matter from the atomic scale (1 Å) to the colloidal one (100 nm). However, papers relating SAXS measurements combined with microfluidics are scarce. This works describes the microfabrication of thin microfluidic devices in polyimide (Kapton) and the fabrication of a simple polyimide-based millifluidic system. These systems are well-suited to perform X-ray scattering measurements using intensed microfocussed beams, as Kapton is both relatively resistant to the high intensities generated by a synchrotron, and almost transparent to X-rays. We show networks of microchannels obtained using laser ablation and fusion bonding between two Kapton films. We also present a simple way to fabricate a polyimide-based steady droplet-generating system. The possibilities offered using such devices are illustrated with X-ray scattering experiments. First, an investigation of a complex fluid undergoing a shear-induced transition in a microchannel was successfully performed. Then, structural and composition data were reached by coupling SAXS measurements and flowing droplets within a polyimide millifluidic capillary. These experiments demonstrate that structural measurements in the 1 Å-20 nm range can be obtained with a spatial resolution of a few microns.