CO2 induced phase transition on a self-standing droplet studied by X-ray scattering and magnetic resonance
Journal article, 2025

Hypothesis: Acoustic levitation is a suitable approach for studying processes occurring at the gas–liquid interfaces, as it allows its investigation in a contact-free manner while providing control over the gas phase. Here, we hypothesize that phase transitions induced by a CO2 rich atmosphere can be examined, at different length scales, in a contact-free manner. Experimental: A system consisting of 12-hydroxysteric acid (HSA) soaps mixed with different ratios of monoethanolamine (MEA) and choline hydroxide, was prepared. Microliter droplets of the samples were acoustically levitated and monitored with a camera, while exposed to CO2 to modify the pH through diffusion at the air–liquid interface and inside the droplet. The phase transition and water mobility in the levitated droplets were evaluated through X-ray scattering (SAXS/WAXS) and magnetic resonance studies, in real-time. Finally, the droplets were collected and examined under the microscope. Findings: The introduction of CO2 gas induced a phase transition from micelles to multi-lamellar tubes, resulting in a gel-like behavior both in the bulk and at the interface. The high stability of the acoustic levitator allowed the investigation of this dynamic phenomenon, in real-time, in a contact-free environment. This study showcases the suitability of acoustic levitation as a tool to investigate complex chemical processes at interfaces.

Self-assembly

Kinetics

Acoustic levitation

In-situ

CO responsive 2

Author

Smaragda Maria Argyri

University Paris-Saclay

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Maëva Almeida

Institut de Chimie et des Matériaux de Paris Est (ICMPE) - UMR7182

University Paris-Saclay

Fabrice Cousin

University Paris-Saclay

Lars Evenäs

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Anne Laure Fameau

University of Lille

Clémence Le Coeur

University Paris-Saclay

Institut de Chimie et des Matériaux de Paris Est (ICMPE) - UMR7182

Romain Bordes

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Journal of Colloid and Interface Science

0021-9797 (ISSN) 1095-7103 (eISSN)

Vol. 678 1181-1191

Subject Categories

Analytical Chemistry

DOI

10.1016/j.jcis.2024.09.123

PubMed

39342863

More information

Latest update

10/4/2024