Klein, Regina and Dutton, Helen and Diat, Olivier and Tiddy, Gordon J. T. and Kunz, Werner (2011) Thermotropic Phase Behavior of Choline Soaps. JOURNAL OF PHYSICAL CHEMISTRY B, 115 (14). pp. 3838-3847. ISSN 1520-6106,
Full text not available from this repository. (Request a copy)Abstract
Choline carboxylates (ChCm with m = 12-18) are simple biocompatible anionic surfactants with very low Krafft temperatures, possessing a rich aqueous phase behavior. In the present work, we have investigated the thermotropic mesomorphism of anhydrous ChCm salts for m = 12-18. Transition temperatures and enthalpies determined by differential scanning calorimetry reveal that all investigated compounds exhibit three different phases between -20 and 95 degrees C. The phases were further characterized by optical polarizing microscopy, NMR spin-spin relaxation, and X-ray scattering measurements. The nature of the phases was identified with increasing temperature as crystalline, semicrystalline, and liquid-crystalline lamellar. Even long-chain choline carboxylates (m = 18) were found to melt into a lamellar liquid-crystalline phase below 100 degrees C. Accordingly, with choline as counterion in simple fatty acid soaps, not only the water solubility is considerably enhanced but also the melting points are substantially reduced, hence facilitating thermotropic mesomorphism at temperatures between 35 and 95 degrees C. Thus, simple choline soaps with m = 12-18 may be classified as ionic liquids.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | STRUCTURE DES SAVONS; NUCLEAR-MAGNETIC-RESONANCE; ANHYDROUS SODIUM SOAPS; SPIN-SPIN RELAXATION; LIQUID-CRYSTALS; IONIC LIQUIDS; OPTICAL MICROSCOPY; HYDROCARBON CHAINS; POTASSIUM CAPRATE; WATER-SYSTEMS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Werner Kunz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 22 Jun 2020 07:20 |
| Last Modified: | 22 Jun 2020 07:20 |
| URI: | https://pred.uni-regensburg.de/id/eprint/20958 |
Actions (login required)
 |
View Item |
