Amidoamine Oxide Surfactants as Low-Molecular-Weight Hydrogelators: Effect of Methylene Chain Length on Aggregate Structure and Rheological Behavior.

Content Provider	Europe PMC
Author	Kakehashi, Rie Tokai, Naoji Nakagawa, Makoto Kawasaki, Kazunori Horiuchi, Shin Yamamoto, Atsushi
Editor	Nigro, Valentina Limosani, Francesca
Copyright Year	2023
Abstract	Rheology control is an important issue in many industrial products such as cosmetics and paints. Recently, low-molecular-weight compounds have attracted considerable attention as thickeners/gelators for various solvents; however, there is still a significant need for molecular design guidelines for industrial applications. Amidoamine oxides (AAOs), which are long-chain alkylamine oxides with three amide groups, are surfactants that act as hydrogelators. Here, we show the relationship between the length of methylene chains at four different locations of AAOs, the aggregate structure, the gelation temperature Tgel, and the viscoelasticity of the formed hydrogels. As seen from the results of electron microscopic observations, the aggregate structure (ribbon-like or rod-like) can be controlled by changing the length of methylene chain in the hydrophobic part, the length of methylene chain between the amide and amine oxide groups, and the lengths of methylene chains between amide groups. Furthermore, hydrogels consisting of rod-like aggregates showed significantly higher viscoelasticity than those consisting of ribbon-like aggregates. In other words, it was shown that the gel viscoelasticity could be controlled by changing the methylene chain lengths at four different locations of the AAO.
Journal	Gels
Volume Number	9
PubMed Central reference number	PMC10048289
Issue Number	3
PubMed reference number	36975709
e-ISSN	23102861
DOI	10.3390/gels9030261
Language	English
Publisher	MDPI
Publisher Date	2023-03-22
Access Restriction	Open
Rights License	Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). © 2023 by the authors.
Subject Keyword	amidoamine oxide amine oxide surfactant low-molecular-weight gelator hydrogel gelation temperature aggregate structure methylene chain length electron microscopy rheology control supramolecular gel
Content Type	Text
Resource Type	Article
Subject	Bioengineering Biomaterials Polymers and Plastics Organic Chemistry