Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol

Banerjee, Saikat and Bagchi, Biman (2013) Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol. In: JOURNAL OF CHEMICAL PHYSICS, 139 (16).

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Abstract

In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tertbutyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures. (C) 2013 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	JOURNAL OF CHEMICAL PHYSICS
Publisher:	AMER INST PHYSICS
Additional Information:	copyright for this article belongs to AMER INST PHYSICS, CIRCULATION & FULFILLMENT DIV,USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	23 Dec 2013 05:27
Last Modified:	23 Dec 2013 05:27
URI:	http://eprints.iisc.ac.in/id/eprint/47966

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