Novel gemini micelles from dimeric surfactants with oxyethylene spacer chain. Small angle neutron scattering and fluorescence studies

De, Soma and Aswal, Vinod K and Goyal, Prem S and Bhattacharya, Santanu (1998) Novel gemini micelles from dimeric surfactants with oxyethylene spacer chain. Small angle neutron scattering and fluorescence studies. In: Journal of Physical Chemistry B, 102 (32). pp. 6152-6160.

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Abstract

Three new gemini surfactants containing mono-, di-, and trioxyethylene spacer chains have been synthesized. Small angle neutron scattering (SANS) cross sections from the micellar aggregates of these dimeric amphiphiles Br-, n-C16H33NMe2+-CH2(CH2OCH2)(p)CH2-N+Me2-n-C16H33,Br-, (where p = 1, 2, and 3) in aqueous media (D2O) have been measured. The data have been analyzed using the Hayter and Penfold model for macro-ion solution to compute the interparticle structure factor S(Q) taking into account the screened Coulomb interactions between the dimeric micelles. The SANS analysis showed that the micellar morphology depends on both the nature and the length of the spacer unit. Detailed analysis of the data further indicates that the introduction of oxyethylene spacer is not sufficient enough to prevent looping of the spacer chain. Thus the average separation between the dimethylammonium ion headgroups is considerably lower than is expected from a fully extended conformation of the spacer chain. The micelles from these surfactants have also been characterized in terms of their critical micelle concentrations (cmc), microviscosities, and micropolarities on the basis of the information provided by micelle-solubilized fluorescent probes. These results indicate little difference in their micellar properties such as cmc, microviscosity, and micropolarity.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry B
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:	21 Dec 2009 12:19
Last Modified:	19 Sep 2010 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/19028

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