Special Issue of Colloid and Polymer Science in Honor of Professor Dr. Heinz Hoffmann

Special Issue of Colloid and Polymer Science in honor of Professor Dr. Heinz Hoffmann

CPS-2015-0519-Revised- Electronic Supplementary Material for

Ionic liquid-based surfactants with unsaturated head-group: Synthesis and micellar properties of 1-alkyl-3-vinylimidazolium bromides

Naved I Malek,*1,2 Zuber S. Vaid1, Utkarsh U. More,1 and Omar A. El Seoud,*2

1-Applied Chemistry Department, S.V. National Institute of Technology,

Surat- 395 007, Gujarat, India; e-mail:

2- Institute of Chemistry, the University of São Paulo,

P. O. Box 26077, 05513-970, São Paulo, SP; e-mail:

Figure ESM-1: Molecular structures of substances employed in the present work.

Figure ESM-2: Plots of The limiting equivalent conductivity vs C1/2 for (a), C10VnImBr; (b), C12VnImBr, (c), C14VnImBr, (d), C16VnImBr, (e), C16EtImBr.

Figure ESM-3: Dependence of Uv-Vis absorption of solubilized MO on surfactant concentration in mM, at 298.15 K. The symbols are: n, C10VnImBr; , C12VnImBr; ▲, C14VnImBr; q, C16VnImBr; and ¿, C16EtImBr.

Calculations

We employed the following equations for calculations of the parameters of surfactant adsorption and micellization [1-4]

1- Effectiveness of surface tension reduction (πcmc):

(1)

Where g0 and gcmc are the surface tension of the solvent and surface tension at cmc, respectively.

2- Adsorption efficiency (pC20),

(2)

Where C20 is the concentration required to reduce the surface tension of water by 20 mN/m, a point that is required to attain the saturation at the air/water interface.

3- Maximum surface excess concentration Γmax and the minimum area occupied per ILBS, Amin:

(3)

(4)

Where C is the ILBS concentration in bulk solution, R, T and NA have their usual meanings.

4- Standard Gibbs free energy of adsorption ():

(5)

5- Thermodynamics parameters of micellization, including the standard Gibbs free energy (), the standard enthalpy () and entropy ():

(6)

(7)

(8)

(9)

Where Xcmc is the cmc expressed in mole fraction scale. Cm is in mol dm−3, and 55.4 is the molar concentration of water at 298.15 K.

6- The aggregation numbers (Nagg) for the studied ILs were obtained by fluorescence quenching of pyrene using cetylpyridinium chloride (CPC) according to [5]:

(10)

Where I0 and IQ are the fluorescence intensities of pyrene in the absence and presence of quencher CPC, respectively. CQ and CILs are the molar concentrations of quencher (CPC) and ILs, respectively.

References

[1]. Rosen MJ (2004), Surfactants and Interfacial Phenomena, John Wiley & Sons, New Jersey, 3rd ed.

[2]. Tanford C (1980), The Hydrophobic Effect: Formation of Micelles and Biological Membranes, John Wiley, New York.

[3]. Inoue T, Ebina H, Dong B, Zheng L (2007) Electrical conductivity study on micelle formation of long-chain imidazolium ionic liquids in aqueous solution. J. Colloid Interface Sci. 314: 236–241.

[4]. Wei Y, Wang F, Zhang Z, Ren C, Lin Y (2014) Micellization and Thermodynamic Study of 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids in Aqueous Solution J. Chem. Eng. Data 59: 1120−1129.

[5]. Turro NJ, Yekta A (1978) Luminescent probes for detergent solutions. A simple procedure for determination of the mean aggregation number of micelles. J. Am. Chem. Soc. 100: 5951–5952.