(51e) Isolating Non-Gravitational Ageing Phenomena in Emulsions Utilizing Microgravity and Diffusing Wave Spectroscopy
AIChE Annual Meeting
2022
2022 Annual Meeting
Engineering Sciences and Fundamentals
Colloidal Dispersions
Monday, November 14, 2022 - 9:00am to 9:15am
For many emulsions studied on earth, gravitational separation is typically the dominating mechanism of destabilization and can obscure the other three ageing processes. In collaboration with the European Space Agency (ESA), the PASTA mission studies emulsion stability in the condition of microgravity using the Soft Matter Dynamics (SMD) module â a diffusing wave spectroscopy (DWS) facility â in the Fluid Sciences Laboratory on the International Space Station (ISS). Emulsions are created using magnetic actuation of a piston in sealed sample cells containing oil, water, and surfactant. The dynamics of the emulsion are recorded via an overview camera, a line camera, and an avalanche photodiode. Photon correlation for DWS in both forward and backscattering is calculated. DWS provides volume-averaged insight into the displacements of emulsion droplets allowing extraction of droplet size, frequency of droplet rearrangements, and optical properties over the lifetime of an emulsion. Similar emulsions are prepared and studied on ground-based replicas of the SMD to provide complimentary data points and disentangle ageing mechanisms. We report trends in extracted physical parameters and a workflow to statistically analyze relevant effects of non-ionic surfactant concentrations. Additionally, we compare trends for emulsion formulations studied on the ISS and on earth to determine how the mechanisms of destabilization may be quantified using DWS.