Time-resolved X-ray microscopy of nanoparticle aggregates under oscillatory shear

TL;DR

This paper demonstrates the use of time-resolved X-ray microscopy with a piezo-driven shear cell to observe nanoparticle aggregate reorganization under oscillatory shear, opening new avenues for studying nanoscale structural dynamics.

Contribution

First implementation of shear experiments in an X-ray microscope enabling direct observation of nanoparticle structural dynamics in suspension.

Findings

Shear-induced reorganization of magnetite nanoparticle aggregates was observed.

X-ray microscopy is suitable for studying structural changes at small length scales.

The setup allows precise application of mechanical stimuli during imaging.

Abstract

Of all current detection techniques with nanometer resolution, only X-ray microscopy allows imaging nanoparticles in suspension. Can it also be used to investigate structural dynamics? When studying response to mechanical stimuli, the challenge lies in applying them with precision comparable to spatial resolution. In the first shear experiments performed in an X-ray microscope, we accomplished this by inserting a piezo actuator driven shear cell into the focal plane of a scanning transmission X-ray microscope (STXM). Thus shear-induced reorganization of magnetite nanoparticle aggregates could be demonstrated in suspension. As X-ray microscopy proves suitable for studying structural change, new prospects open up in physics at small length scales.