Surface and solution properties of single and mixed gemini/conventional micelles on solubilization of polycyclic aromatic hydrocarbons

Abstract

The surface properties and mixed micellization behaviour of single gemini bis(hexadecyldimethylammonium) pentane dibromide (G5) surfactant, three conventional surfactants (Cationic cetyltrimethylammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS) and nonioinic Polyethylene glycol dodecyl ether (Brij35)) and their equimolar binary mixtures have been investigated by surface tension and spectrophotometry methods at 300K. The critical micelle concentration (CMC), surface properties, <img src='http://www.niscair.res.in/jinfo/gamma1.gif' border=0>_max (maximum surface excess), A_min (minimum surface area per molecule) and <span style="font-family:Symbol;mso-bidi-font-family:" cambria="" math";letter-spacing:="" -.1pt"="" lang="EN-GB">π_CMC (surface pressure at the CMC) have been determined. The deviation from the ideal of the mixed micelles has been discussed on the basis of Clint theory. For mixed systems, regular solution theory (Rubingh) and Rosen’s theories are used, which helps to evaluate the composition of the mixed micelle, the activity coefficient, and interaction parameters (β and β^{<span style="mso-char-type:symbol;mso-symbol-font-family:Symbol;mso-bidi-font-weight: bold">σ</span>}). Negativity of interaction parameters (β and β^σ) for mixed micelle formation indicates attractive interaction for all the system.

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