Composition dependent non-ideality in aqueous binary mixtures as a signature of avoided spinodal decomposition

Sarkar, Sarmistha and Banerjee, Saikat and Roy, Susmita and Ghosh, Rikhia and Ray, Partha Pratim and Bagchi, Biman (2015) Composition dependent non-ideality in aqueous binary mixtures as a signature of avoided spinodal decomposition. In: JOURNAL OF CHEMICAL SCIENCES, 127 (1). pp. 49-59.

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Abstract

We explore the potential energy landscape of structure breaking binary mixtures (SBBM) where two constituents dislike each other, yet remain macroscopically homogeneous at intermediate to high temperatures. Interestingly, we find that the origin of strong composition dependent non-ideal behaviour lies in its phase separated inherent structure. The inherent structure (IS) of SBBM exhibits bi-continuous phase as is usually formed during spinodal decomposition. We draw analogy of this correlation between non-ideality and phase separation in IS to explain observation of non-ideality in real aqueous mixtures of small amphiphilic solutes, containing both hydrophilic and hydrophobic groups. Although we have not been able to obtain IS of these liquids, we find that even at room temperature these liquids sustain formation of fluctuating, transient bi-continuous phase, with limited lifetime (tau less than or similar to 20 ps). While in the model (A, B) binary mixture, the non-ideal composition dependence can be considered as a fluctuation from a phase separated state, a similar scenario is expected to be responsible for the unusually strong non-ideality in these aqueous binary mixtures.

Item Type:	Journal Article
Publication:	JOURNAL OF CHEMICAL SCIENCES
Publisher:	INDIAN ACAD SCIENCES
Additional Information:	Copy right for this article belongs to the INDIAN ACAD SCIENCES, C V RAMAN AVENUE, SADASHIVANAGAR, P B #8005, BANGALORE 560 080, INDIA
Keywords:	Non-ideality; binary mixture; inherent structures; spinodal decomposition; computer simulation
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	21 Apr 2015 07:10
Last Modified:	21 Apr 2015 07:10
URI:	http://eprints.iisc.ac.in/id/eprint/51320

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