Near-Field Ptychographic Tomography on Freeze-Quenched Liquids Using CryoTEM Methods

In materials chemistry, there is currently intense debate on the nature of non-classical phases that form as precursors to crystalline materials: are they true thermodynamic phases or simply mixing heterogeneities? To date, neither case has been demonstrated conclusively. The goal of this proposal is to use cryogenic near-field ptychographic X-ray computed tomography (3DNFP) to obtain quantitative information from these elusive phases and settle the debate. Aqueous solutions of cerium oxalate undergoing non-classical crystallization will be cryo-quenched at multiple reaction times to determine the size, volume fraction, and density of transient phases over time to assess their thermodynamic/ kinetic nature. We also address the panel’s comments from the previous call and emphasize that the preparation of samples on 2D TEM grids is a routine method in our lab with no risk of ice formation and that the previous beamtime showed no risk of radiation damage.