Small-angle neutron scattering studies of different mixed micelles composed of dimeric and monomeric cationic surfactants

De, Soma and Aswal, Vinod K and Goyal, Prem S and Bhattacharya, Santanu (1997) Small-angle neutron scattering studies of different mixed micelles composed of dimeric and monomeric cationic surfactants. In: Journal of Physical Chemistry B, The, 101 (29). pp. 5639-5645.

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Abstract

Measurements of small-angle neutron scattering (SANS) cross sections from different mixed micelles composed of CTAB and Br-, n-C16H33N+Me2-(CH2)(m)N+Me2-n-C16H33, Br- (16-m-16, 2Br(-), where m = 3, 5, and 10), in aqueous media (D2O) are reported. The data have been analyzed using the Hayter and Penfold model for macroion solution to compute the interparticle structure factor S(Q) taking into account the screened Coulomb interactions between the micelles. The aggregate composition matches with that predicted from an ideal mixing model. The SANS analysis further indicates that the extent of aggregate growth and the Variations of shapes of the mixed micelles could be modulated by the amount of dimeric surfactant present in these mixtures. With the spacer chain length m less than or equal to 4 in the dimeric surfactant, the propensity of micellar growth is particularly pronounced. The effect of the variation of the temperature for the mixed micellar system (23.1 mol % of 16-3-16, 2Br(-)) was also examined. The systemic microviscosities that the mixed micellar aggregates offer to a solubilized, extrinsic fluorescence probe, 1,6-diphenyl-1,3,5-hexatriene, were determined. The variation of the microviscosities of the mixed micelles as a function of percentages of the dimeric surfactants could be explained in terms of conformational variations and progressive looping of the spacer chain of dimeric surfactants in mixed micellar aggregates with increasing m values.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry B, The
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	30 Jun 2011 12:05
Last Modified:	30 Jun 2011 12:05
URI:	http://eprints.iisc.ac.in/id/eprint/38456

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