Fluid interface calorimetry

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Garrido, PF (Author) Other; Bastos, M (Author) FCUP; Velazquez Campoy, A (Author) Other; Dumas, P (Author) Other; Pineiro, A (Author) Other

Journal

Title: Journal of Colloid and Interface Science

Vol. 596

Pages: 119-129

ISSN: 0021-9797

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-00T-S8F

DOI: 10.1016/j.jcis.2021.03.098

Abstract (EN): Hypothesis: Amphiphilic molecules spontaneously adsorb to fluid polar-nonpolar interfaces. The time scale of such adsorption depends on the molecular size and structure of the solute. This process should be accompanied by a power heat exchange that could be detected by commercial isothermal calorimeters. Experiments: Air is injected in the bulk of different aqueous solutions contained in the sample cell of an isothermal titration calorimeter. The formation of the resulting bubbles leads to a liquid/air interface to which the solute molecules spontaneously adsorb. Continuous injection experiments to produce multiple bubbles as well as experiments with static bubbles stand from the capillary tip, aiming to observe slow adsorption processes, were performed. Findings: The power associated with the formation, growth and release of air bubbles in different liquids was measured. Different independent contributions that can be associated to the pressure change in the gas phase, the evaporation-condensation of the solvent, the increase of interfacial area, the change in the heat capacity of the sample cell content, and the release of the bubble were observed. The periodic pattern produced by the continuous injection of air at a constant rate is used to determine the surface tension of different liquids, including solutions of different molecules and (bio)macromolecules.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11