Temperature-sensitive properties of occluded hydration centers in direct hexagonal (HI) mesophases

Temperature-induced structural transformations of a direct hexagonal mesophase were investigated by SAXS, rheology, DSC, and NMR. The investigated mesophase region consists of two distinct direct hexagonal structures. The primary structure, detected at lower water content (33.0–39.0 wt%, 25 °C), is...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2021-12, Vol.631, p.127709, Article 127709
Hauptverfasser: Goldmünz, Eliezer, Aserin, Abraham, Garti, Nissim
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Temperature-induced structural transformations of a direct hexagonal mesophase were investigated by SAXS, rheology, DSC, and NMR. The investigated mesophase region consists of two distinct direct hexagonal structures. The primary structure, detected at lower water content (33.0–39.0 wt%, 25 °C), is oriented as a bidiscontinuous assembly; it is composed of "occluded hydration centers" (OHCs) and direct surfactant-oil aggregates. The secondary structure, detected at higher water content (39.5–42.5 wt% water, 25 °C), is composed of an unbound water continuous phase and direct surfactant-oil aggregates. The OHCs within the bidiscontinuous mesophase were found to enhance the mesophase's order (correlation length (ξ)) and storage modulus (G′). The content of the unbound water occluded within the OHCs is temperature dependent, due to the ethoxylates’ water binding properties. At temperatures below 18 °C, the water in the bidiscontinuous mesophase (
ISSN:0927-7757
1873-4359
DOI:10.1016/j.colsurfa.2021.127709