Study of the formation and solution properties of worm-like micelles formed using both N-hexadecyl-N-methylpiperidinium bromide-based cationic surfactant and anionic surfactant.

The viscoelastic properties of worm-like micelles formed by mixing the cationic surfactant N-hexadecyl-N-methylpiperidinium bromide (C16MDB) with the anionic surfactant sodium laurate (SL) in aqueous solutions were investigated using rheological measurements. The effects of sodium laurate and temperature on the worm-like micelles and the mechanism of the observed shear thinning phenomenon and pseudoplastic behavior were systematically investigated. Additionally, cryogenic transmission electron microscopy images further ascertained existence of entangled worm-like micelles

Aggregation Behavior of Long-Chain Piperidinium Ionic Liquids in Ethylammonium Nitrate

Micelles formed by the long-chain piperidinium ionic liquids (ILs) N-alkyl-N-methylpiperidinium bromide of general formula CnPDB (n = 12, 14, 16) in ethylammonium nitrate (EAN) were investigated through surface tension and dissipative particle dynamics (DPD) simulations. Through surface tension measurements, the critical micelle concentration (cmc), the effectiveness of surface tension reduction (Πcmc), the maximum excess surface concentration (Гmax) and the minimum area occupied per surfactant molecule (Amin) can be obtained. A series of thermodynamic parameters (DG0 m, DH0 m and DS0 m) of micellization can be calculated and the results showed that the micellization was entropy-driven. In addition, the DPD simulation was performed to simulate the whole aggregation process behavior to better reveal the micelle formation process

Temperature effect plots.

<p>(a) The zero shear viscosity as a function of temperature for the 70 mM C₁₆MDB/40 mM SL solution; (b) the frequency sweep of 70 mM C₁₆MDB/40 mM SL system at different temperatures.</p

Cryo-TEM images.

<p>(a) Cryo-TEM image of the 70 mM C₁₆MDB/35 mM SL solution; (b) Cryo-TEM image of the 70 mM C₁₆MDB/40 mM SL solution.</p

Steady rheology plots.

<p>(a) Steady rheology plots for 70 mM C₁₆MDB with different SL concentrations at <i>T</i> = 25°C; (b) Variations of zero-shear viscosity () as a function of different SL concentrations for the 70 mM C₁₆MDB.</p

Shear stress with different concentration of SL at a fixed C₁₆MDB concentration of 70 mM.

<p>Shear stress with different concentration of SL at a fixed C₁₆MDB concentration of 70 mM.</p

Various rheological parameters calculated for the sample of 70 mM C₁₆MDB/40 mM SL at different temperatures.

<p>Various rheological parameters calculated for the sample of 70 mM C₁₆MDB/40 mM SL at different temperatures.</p

Dynamic oscillatory plots.

<p>(a) Variations of G′ and G″ as a function of frequency (<i>ω</i>) in aqueous 70 mM C₁₆MDB/35 mM SL solution; (b) Cole–Cole plots (solid lines indicate the best fitting of Maxwell model).</p

Energy calculation plots.

<p>(a) An Arrhenius plot of ln<i>τ</i>_R as a function of 1/T for the 70 mM C₁₆MDB/40 mM SL solution; (b) the plot of ln (G″_min/G₀) as a function of 1/T.</p