Mixed micelle formation of cationic gemini surfactant with anionic bile salt: a PAH solubilization study

Rahman

Rana

et al. 2018

J Surfact & Detergents

A conductometric study of the mixed micellization behavior between cetyltrimethylammonium bromide (CTAB, a cationic surfactant) and sodium dodecyl sulfate (SDS, an anionic surfactant) was carried out in the absence/presence of various percentages of chitosan in the temperature range of 298.15–318.15 K. The deviations of critical micelle concentration (cmc) from the ideal values indicate the interaction between CTAB and SDS. The micellar mole fraction values according to different proposed models X1Rub (Rubingh), X1M (Motomura), X1Rod (Rodenas), and X1id (ideal mole fraction) were estimated and the results obtained reveal the high contribution of CTAB in the mixed micellization, which enhances with the increase of the mole fraction of CTAB. The negative magnitudes of normalΔGm0 indicate the spontaneous formation of mixed micelles between CTAB and SDS. The values of activity coefficients (f1 and f2) were less than unity and the values of the interaction parameter (β) are negative in all cases, which indicate the attractive interaction between CTAB and SDS. The negative values of excess free energy of micellization (ΔGex) signify the stability of the mixed micelles. The negative values of normalΔHm0 in the chitosan systems indicate that micellization is exothermic. The values of normalΔSm0 were found to be positive in all cases.

Section: Resultssupporting

confidence: 92%

Aggregation Behavior of Sodium Dodecyl Sulfate and Cetyltrimethylammonium Bromide Mixtures in Aqueous/Chitosan Solution at Various Temperatures: An Experimental and Theoretical Approach

Rahman

Rana

et al. 2018

J Surfact & Detergents

“…Dealing with regular solution theory, for a certain solution mixture β should remain independent of mole fraction that is not recognized experimentally. Herein, the β was obtained to be composition dependent similar to previously reported in case of anionic‐cationic mixed systems …”

Section: Resultssupporting

confidence: 68%

Mixed micellization study of dodecyltrimethylammonium chloride and cetyltrimethylammonium bromide mixture in aqueous/urea medium at different temperatures: Theoretical and experimental view

J of Physical Organic Chem

Rub

Hoque

et al. 2018

The behavior of mixed micelle formation between two cationic surfactants‐dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium bromide (CTAB) in absence/attendance of urea has been investigated by means of conductivity measurements over temperature range of 298.15 to 318.15 K. Lower magnitudes of the critical micelle concentration from their ideal values imply the strong interaction between the studied amphiphiles. The micellar mole fraction (X1) on the basis of the different proposed model (Rubingh, Motomura & Rodenas) and the ideal micellar mole fraction (Xid) were evaluated, and estimated results imply the high contribution of CTAB in the mixed micelle formation that enhances with the augment of the mole fraction of the CTAB. The values of activity coefficients (f1 and f2) (less than unity) and negative values of the interaction parameter (β) in all cases signify the attractive interaction between the amphiphiles studied. Spontaneous mixed micelle formation between the studied amphiphiles (dodecyltrimethylammonium chloride and CTAB) was indicated by the negative magnitudes of free energy of micellization (ΔGm0). The negative values of excess free energy of micellization (ΔGex) indicate the higher stability of the mixed micelle compared with the single micelle. The standard enthalpy change of micellization (ΔHm0) and standard entropy change of micellization (ΔSm0) were also calculated and discussed.

“…According to the regular solution theory (RST), β should be independent of composition for a certain solution mixture that is not experimentally recognized. In this current study, the β values were attained to be composition‐dependent, similar to previously reported values in the literature for ionic mixed systems . As stated, there are more interaction between the oppositely charged surfactants mixtures as compared with the surfactants mixtures having the same charge.…”

Section: Resultssupporting

confidence: 87%

Influence of NaCl/urea on the aggregation behavior of dodecyltrimethylammonium chloride and sodium dodecyl sulfate at varying temperatures and compositions: Experimental and theoretical approach

J of Physical Organic Chem

Rub

Hoque

et al. 2018

Aggregation behavior of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium chloride (DTAC) has been studied by conductivity measurement in aqueous/urea/NaCl medium. The deviation of experimentally executed critical micelle concentration (cmc) from their respective ideal values (cmc id ) signifies the interaction between the studied surfactants. The experiments were performed at different temperatures in order to estimate different thermodynamic parameters. The negative values of Gibbs free energy (ΔG m o ) point out the feasibility of the micellization behavior of the mixed systems as well as validate the feasibility of SDS-DTAC interactions. The micellar mole fraction (X 1 ) and the activity coefficients ( f 1 and f 2 ) on the basis of different proposed model (Rubingh, Motomura, & Rodenas) andideal mole fraction (X id ) were estimated, and obtained results illustrate the high contribution of DTAC in the mixed micellization, which exacerbates with the increase of the mole fraction of the DTAC. The interaction parameter (β) has also been investigated to get detailed insights of the interactions between the surfactants by concerning theoretical model proposed by Rubingh. The ΔG ex values were attained to be negative at all α 1 and temperatures, showing that mixed micelles are more stable than micelles of individual surfactants.