Thermotropic behavior of asymmetric chain length catanionic surfactants: The influence of the polar head group

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Silva, BFB (Author) Other; Marques, EF (Author) FCUP

Journal

Title: Journal of Colloid and Interface Science

Vol. 290

Pages: 267-274

ISSN: 0021-9797

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 57 Citations

Scopus - 59 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-14M

DOI: 10.1016/j.jcis.2005.04.012

Abstract (EN): Catanionic surfactants formed by the pairing of two ionic amphiphilic chains of opposite charge are now recognized as an important class of amphiphiles. Many aspects of their phase behavior have yet to be explored. In this work, two homologous series of catanionic surfactants were synthesized, based on the cationic headgroups trimethylammonium and pyridinium. Within each series, the headgroup and chain length of the cationic counterpart remains constant while for the anionic counterpart the headgroup is varied, while its alkyl chain length is also kept constant. Thus, one can directly monitor the influence of headgroup chemistry on the thermal behavior of these compounds. Differential scanning calorimetry (DSC) and polarizing light microscopy show that these compounds bear a rich and often complex thermotropic behavior, with the headgroup chemistry in some instances having a rather dramatic influence on phase behavior. Several liquid crystalline phases appear between the solid crystalline phase and the isotropic liquid phase. A qualitative correlation between the observed thermotropic behavior and the chemical nature of headgroup, is presented.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8