Self-Assembly of Long-Chain Betaine Surfactants: Effect of Tailgroup Structure on Wormlike Micelle Formation.
Langmuir
; 34(3): 970-977, 2018 01 23.
Article
in En
| MEDLINE
| ID: mdl-29016147
ABSTRACT
Long-chain amidopropyl betaines are known for their ability to self-assemble into viscoelastic wormlike micellar structures. Here, we explore the effect of tailgroup molecular architecture on this process, comparing five molecules, each with C18 chains but different levels of unsaturation and branching. The surfactants are synthesized from stearic, oleic, linoleic, linolenic, and isostearic acids. The self-assembly of these molecules in aqueous solutions is explored using small- and ultra-small-angle neutron scattering (SANS and USANS). It is seen that optimum wormlike micelle formation is achieved for the oleic-chained surfactant, and the alignment of self-assembled structures is further explored using rheo-SANS. The more highly unsaturated molecules form rodlike micelles, whereas the stearic-tailed molecule shows a pronounced Krafft point and the isostearic-chained surfactant is entirely water-insoluble. These results demonstrate the critical importance of tailgroup geometry on surfactant properties and self-assembly for this industrially important class of surfactants.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Surface-Active Agents
/
Betaine
/
Micelles
Language:
En
Journal:
Langmuir
Journal subject:
QUIMICA
Year:
2018
Document type:
Article
Affiliation country:
Australia
Country of publication:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA