Fluid interface calorimetry

• Tipo: Artigo em Revista Científica Internacional
• Data: 2021

Autores

Garrido, PF (Autor) Outra; Bastos, M (Autor) FCUP; Velazquez Campoy, A (Autor) Outra; Dumas, P (Autor) Outra; Pineiro, A (Autor) Outra

Revista

Título: Journal of Colloid and Interface Science

Vol. 596

Páginas: 119-129

ISSN: 0021-9797

Editora: Elsevier

Indexação

ISI Web of Knowledge - 3 Citações

Scopus - 4 Citações

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 11