Abstract
Understanding morphological transformations upon temperature-induced mesophase transitions offers mecha-nistic insights into the self-assembly process. We have recently reported the unexpected formation of a micro-fibrillar lamellar gel in SDS-glycerol mixtures above a critical gelation concentration (CGC) as low as ~2 wt%. The gel phase comprised a fibrillar structure on the microscale and a lamellar structure on the nanoscale. Here, the nanoscopic structure of the gel as a function of temperature was probed with small-angle neutron scattering (SANS). The gel underwent a gel-to-fluid transition at a critical gelation temperature, TGC =45 ◦C, forming cylindrical micelles at elevated temperatures. Upon cooling, a hexagonal phase formed at ~TGC, evident from the SANS Bragg peaks. This hexagonal phase upon the fluid-to-gel transition sheds light on the gelation mechanism, in which self-assembled SDS micelles undergo a cylindrical-to-lamellar morphological transition via a hexagonal phase. This unprecedented observation also highlights the complexity of self-assembly in nonaqueous hydrogen- bonding rich media.
Original language | English |
---|---|
Article number | 100342 |
Number of pages | 5 |
Journal | Colloid and Interface Science Communications |
Volume | 40 |
Early online date | 13 Dec 2020 |
DOIs | |
Publication status | Published - 1 Jan 2021 |
Keywords
- Glycerol
- SDS
- Surfactant mesophases
- Nonaqueous H-bonding solvents
- Small-angle neutron scattering
- Self-assembly
- Gelation
- Low molecular-weight gels
- Lamellar phase
- Hexagonal phase