The effect of glycols and their ethers on micellar behavior of cetyltrimethylammonium tosylate

- Worm-like CTAT micelles size can be tune with EG, DEG, PG, DPG and their ethers.
- EG and DEG can shift monomer ↔ micelle equilibrium and give maximum in viscosity.
- EGMHE and DEGMHE solubilize CTAT molecules and decrease micelles size.
- PG, DPG and their ethers decrease worm-like micelle size without giving maximum.

The effect of glycols viz., ethylene glycol (EG), diethylene glycol (DEG) propylene glycol (PG), dipropylene glycol (DPG) and their monoalkyl ethers on the morphological features of cetyltrimethylammonium tosylate (CTAT) micelle was examined from viscosity and small angle neutron scattering (SANS) measurements. EG and DEG, and their short chain ethers showed an initial increase in viscosity followed by a decrease while long chain PG, DPG and their ethers showed a monotonous decrease in viscosity. SANS results support the viscosity behavior. These trends are explained on the basis of hydrophobicity of the additives that determines its location in the micelle exerting an effect on micelle morphology. The critical micelle concentrations (CMCs) of CTAT determined tensiometrically for selected systems are also reported. This study helps in fine tuning of rheology of micellar systems in the presence of gycols and their ethers often used with surfactant systems.