Manorama Panda

Solubilization of polycyclic aromatic hydrocarbons by novel biodegradable cationic gemini surfactant ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride and its binary mixtures with conventional surfactants

The aqueous solubility enhancement of the polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene was investigated by means of micellar solubilization. The solubilization capacity of equimolar binary mixed surfactant solutions of a biodegradable ester-bonded cationic gemini surfactant ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride (C16H33(CH3)2N+(CH2COOCH2)2N+(CH3)2C16H33·2Cl−, 16-E2-16) with cationic cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium chloride (CTAC); anionic sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS); nonionic polyoxyethylene (20) cetyl ether (Brij 58) and Triton X-100 (TX-100) towards the PAHs were studied spectrophotometrically. The solubilization capabilities have been discussed in terms of molar solubilization ratio (MSR), micelle–water partition coefficient (Km) and free energy of solubilization (ΔG0S) of the PAHs. While studying the surface and micellar properties of the single/mixed equimolar gemini–conventional surfactant systems by conductometric, tensiometric and fluorescence quenching methods, synergism between the component surfactants in the mixed micellar solutions was observed. The gemini–anionic surfactant mixtures show better solubilization capacity than the gemini–cationic and gemini–nonionic surfactant mixtures.

Synthesis, Characterization and Solution Properties of Novel Cationic Ester-Based Gemini Surfactants

Abstract The present investigation involves the synthesis of a series of novel green ethylene oxide-linked diester-functionalized cationic gemini surfactants 2,2′-[(oxybis(ethane-1,2-diyl))bis(oxy)]bis(N-alkyl-N,N-dimethyl-2-oxoethanaminium) dichloride (Cm-DEG-Cm; m = 12, 14, 16). These compounds were characterized by 1H-NMR, MS-ESI (+), FT-IR spectroscopy and elemental analysis; their solution properties were evaluated by surface tension and rheology measurements. The dimeric surfactant, Cm-DEG-Cm, possesses improved physicochemical properties as compared to its monomeric counterpart. Much lower critical micelle concentration (cmc) makes the cationic gemini surfactants more useful for the biomedical, pharmaceutical, industrial and academic sectors. Longer the alkyl chain of surfactants lower are the cmc values, the order is C16-DEG-C16 < C14-DEG-C14 < C12-DEG-C12. For all the three synthesized gemini surfactants no cloud point was noticed in between the temperatures 0 °C to 100 °C at the concentrations 0.002 mM, 0.02 mM and 0.2 mM of the aqueous surfactant solutions which is a beneficial factor for the use of these amphiphiles in various areas of application.

Formation of Mixed Micelles of the Environmentally Acceptable Oxy-Diester-Linked Gemini Surfactants with Brij 58

Abstract Three oxy-diester-linked cationic gemini surfactants (2,2′-[(oxybis(ethane-1,2-diyl))bis(oxy)]bis(N-alkyl-N,N-dimethyl-2-oxoethanaminium) dichloride, Cm-DEG-Cm (m = 12, 14, 16), were synthesized. The physicochemical properties of the gemini surfactants and their mixtures with Brij 58 were studied by surface tension measurements at various mole fractions and 30°C. The critical micelle concentration (CMC) of the gemini surfactants are smaller than that of their corresponding single-chain counterparts having the same number of carbon atoms in the hydrophobic tail versus polar head. At all investigated compositions, the experimentally obtained CMC values of the surfactant mixtures are smaller than the CMCideal (ideal CMC – CMC of the solution at ideal state); the lower CMC of the mixed systems compared to those the individual surfactants and the negative β values (for both the mixed micelles and monolayers) indicate a synergistic interaction among both the surfactant components. The interaction parameters (βm and βσ) of the mixed surfactant systems were evaluated by using theoretical models. Negative values of β imply an overall attractive force in the mixed state. Also, the free excess energy of mixing was found to be negative for all the systems.

Solubility Enhancement of Polycyclic Aromatic Hydrocarbons by an Eco-Friendly Ester-Linked Gemini Surfactant and its Mixtures with Conventional Surfactants

Abstract The present study deals with the solubility enhancement of the two polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene in the aqueous micellar system of the cationic ester-containing cleavable gemini surfactant ethane-1,2-diyl-bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14 = C14H29(CH3)2N+(CH2COOCH2)2N+(CH3)2C14H29 · 2Cl−)), and its equimolar binary mixtures with some typical conventional cationic, anionic and non-ionic surfactants. The surface tension and conductivity measurements were used to evaluate the physicochemical parameters such as the critical micelle concentration (CMC), the interaction parameter (βm) and Gibbs excess free energy of micellization (ΔGexm) of the systems. The extent of solubilization of the micellar systems towards PAHs has been quantified in terms of molar solublization ratio (MSR), micellar/water partition coefficient (ln Km) and the standard Gibbs free energy of solubilization (ΔGs0). Above the CMC, all studied single as well as binary gemini-conventional surfactant systems show an increase in solubilization of the PAHs. For pure systems, the MSR value of Brij 58 was found to be significantly higher than that of the other amphiphiles. Amongst the mixed surfactant systems, the solubility enhancement of anthracene is found to be maximum in the 14-E2-14 + SDS/SDBS system whereas the system14-E2-14 + Brij 58 shows a higher solubility for pyrene.

Surfactant-polymer interaction: effect of hydroxypropylmethyl cellulose on the surface and solution properties of gemini surfactants

AbstractInteraction of a nonionic polymer hydroxypropylmethyl cellulose (HPMC) with the cationic gemini surfactants, ethane-1,2-diyl bis (N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16), pentanediyl-1,5-bis (dimethylcetylammonium bromide) (16-5-16), hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16), and the conventional surfactant (cetyltrimethylammonium bromide, CTAB) has been investigated by surface tension and rheology measurements. Stronger interaction of HPMC with the geminis as compared to the conventional surfactant is indicated by the values of physicochemical parameters which include the critical aggregation concentration (cac), critical micelle concentration (cmc), ΔG mo

Solubility enhancement of anthracene and pyrene in the mixtures of a cleavable cationic gemini surfactant with conventional surfactants of different polarities

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Environment-friendly ester bonded gemini surfactant: Mixed micellization of 14-E2-14 with ionic and nonionic conventional surfactants

(standard Gibbs free energy of micellization), Γmax (maximum surface excess concentration at the air/solution interface), Amin (minimum area per surfactant molecule), and η (viscosity). Interaction between the surfactant and polymer in the mixed systems results in the formation of polymer-surfactant micelles; strength of the interaction is found to be dependent upon the nature of surfactant. On increasing the polymer concentrations, cac as well as cmc of the surfactant increases. Graphical abstractEffect of [16-E2-16] on the viscosity of polymer solutions at different temperatures and concentrations of HPMC: a 0%, b 0.1%, c 0.5%, and d 1% (w/v)