Supporting information for: Interactional Behaviour of Surface Active Ionic Liquids with Gelling Biopolymer Agarose in Aqueous Medium

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1 Supporting information for: Interactional Behaviour of Surface Active Ionic Liquids with Gelling Biopolymer Agarose in Aqueous Medium Pankaj Bharmoria and Arvind Kumar * Salt & Marine Chemicals Division, CSIR-Central Salt and Marine Chemicals Research Institute, Council of Scientific & Industrial Research (CSIR), G. B. Marg, Bhavnagar- 36, Gujarat, India

2 Annexure S.. Adsorption efficiency pc was calculated from surface tension vs. concentration graphs using equation. pc = log C () Where C is the concentration required to reduce the surface tension of pure solvent or solution by mn m. A higher pc value is indicative of a higher adsorption efficiency of the surfactant at the interface and more efficiency in reducing surface tension.. Surface pressure at cmc, П cmc was calculated from the difference of surface tension of native solution and surface tension at cmc using equation. П cmc = γ o γ cmc () where γ is the surface tension of pure solvent or solution and γ cmc is the surface tension of the solution at cmc. The parameter indicates the maximum reduction of surface tension caused by the dissolution of surfactant molecules and hence becomes a measure for the effectiveness of the surfactant to lower the surface tension of either pure solvent or native solution. 3. Γ max is calculated following the Gibbs adsorption equation 3. max lt nrt C ln C T where n, R, T and [C] are the number of species formed per IL molecule in solution upon ionization (it is for both [C mim][c 8 OSO 3 ]) and [C 8 mim][cl], the universal gas constant, absolute temperature and the molar concentration of IL in solution respectively. The parameter indicates, relative amount of surfactant adsorbed at the interface. Higher surface excess value signifies higher adsorption. Here concentration was used in place of activity, as the solutions used were fairly dilute. -3. A min was obtained from the equation. (3) A min N A max () Where N A is the Avogadro number. 3 Parameter signifies the minimum area occupied by surfactant monomer at the interface. Lower value of A min indicates higher adsorption of monomer at the interface.

3 5. The degree of counter-ion dissociation, α was calculated from the ratio of slope (S /S ) of linear fragments of conductivity profiles of post-micellization(s ) to premicellization (S ) region. Parameter indicates the feasibility of micellization. Lower value of α indicates better binding of counter ion with surfactant head group thus increases the feasibility of micellization. 6. The standard Gibbs free energy of micellization o G m was calculated using equation 5. ln 5 7. The standard Gibbs free energy of interfacial adsorption (ΔG ad ) was calculated using the equation 6. /Γ (6) The parameters of equation (5) and (6) indicate feasibility of micellization in the bulk and adsorption at the interface. Higher negative value of these parameters indicates better feasibility of the process. 3 (A) C 3 (cmc) 8 (B) C 3 (cmc ) 8 /(ms.cm - ) (cmc ) Without Agarose % Agarose C / mmol.kg - ) / (ms.cm - ) / (ms.cm - ) 6 C cmc Without Agarose % Agarose C / (mmol.kg - ) 6 / (ms.cm - ) Fig. S Specific conductance (κ) as a function of IL concentration: (A) [C mim][c 8 OSO 3 ] and (B)[C 8 mim][cl].various transitions are marked with vertical line.( hollow and solid symbols correspond to left and right y-axis respectively)

4 [C(8mim][Cl]inwatedH)/dcof[C8mim][Cl]inwateElectronic Supplementary Material (ESI) for RSC Advances Watts - -3 Watts (A) - -5 (B) Time / (minute) Time / (minute) Fig. S Differential power plots of interaction of Ag with (A) C mim][c 8 OSO 3 ] (B) [C 8 mim][cl] dh / (J.mol - ) cd (dh)/dc -5 dr-55 m6c rc / (mmol.kg-) Fig. S3 ITC thermogram of [C 8 mim][cl] dilution in water. Derivative of thermogram showing transition at cmc.

5 . Pure Ag 58nm.5 mmol.kg - 58 nm 6. mmol.kg - 58 nm -. 3 mmol.kg - 7 nm 5.3 mmol.kg - 7 nm 9.73 mmol.kg - nm mmol.kg - nm 33. mmol.kg - 87 nm 37. mmol.kg - 87 nm -..77mmol.kg - 6nm 7. mmol.kg - 87 nm 5. mmol.kg - 7 nm mmol.kg - 6 nm - Fig. S Hydrodynamic Radii ( ) distributions plotted against normalized intensity of Ag [C mim][c 8 SO 3 ] complexes at various concentrations of [C mim][c 8 SO 3 ] in % agarose solution.

6 . Pure Ag 58nm 3 mmol.kg - 58 nm 9.7 mmol.kg - 75 nm mmol.kg - 73 nm 3.5 mmol.kg nm 6 mmol.kg - 38 nm mmol.kg - nm 69. mmol.kg - nm mmol.kg - nm mmol.kg - 98 nm mmol.kg - 6 nm - Fig. S5 Hydrodynamic Radii ( ) distributions plotted against normalized intensity of Ag-[C 8 mim][cl] complexes at various concentrations of [C 8 mim][cl] in % agarose solution.

complex (bar in images correspond to μm). References:. Chakraborty, T.; Chakraborty, I.; Ghosh, S.

7 (A) (B) µm Fig. S6 SEM micrographs of (A) Native Ag (B) Ag-[C mim][c 8 OSO 3 ] complex, and (C) Ag-[C 8 mim][cl] complex (bar in images correspond to μm). References:. Chakraborty, T.; Chakraborty, I.; Ghosh, S. Langmuir 6,, Chakraborty, T.; Chakraborty, I.; Moulik, S. P.; Ghosh, S. J. Phys. Chem. B 7,, Mitra, D.; Bhattacharya, S. C.; Moulik, S. P. J. Phys. Chem. B 8,, 669.

Module 4: "Surface Thermodynamics" Lecture 22: "" The Lecture Contains: Examples on Effect of surfactant on interfacial tension. Objectives_template

Module 4: Surface Thermodynamics Lecture 22: The Lecture Contains: Examples on Effect of surfactant on interfacial tension. Objectives_template The Lecture Contains: Examples on Effect of surfactant on interfacial tension file:///e /courses/colloid_interface_science/lecture22/22_1.htm[6/16/2012 1:10:07 PM] Example Consider liquid, its vapors and