Phase Transition in Monolayer Water Confined in Janus Nanopore

Kumar, Hemant and Dasgupta, Chandan and Maiti, Prabal K (2018) Phase Transition in Monolayer Water Confined in Janus Nanopore. In: LANGMUIR, 34 (40). pp. 12199-12205.

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Abstract

The ubiquitous nature of water invariably leads to a variety of physical scenarios that can result in many intriguing properties. We investigate the thermodynamics and associated phase transitions for a water monolayer confined within a quasi-two-dimensional nanopore. An asymmetric nanopore constructed by combining a hydrophilic (hexagonal boron nitride) sheet and a hydrophobic (graphene) sheet leads to an ordered water structure at much higher temperatures compared to a symmetric hydrophobic nano pore consisting of two graphene sheets. The discontinuous change in the thermodynamic quantities, potential energy (U), and entropy (S) of confined water molecules computed from the all-atom molecular dynamics simulation trajectories, uncovers a first-order phase transition in the temperature range of T = 320-330 K. Structural analysis reveals that water molecules undergo a disorder-to-order phase transformation in this temperature range with a 4-fold symmetric phase persisting at lower temperatures. Our findings predict a novel confinement system which has the melting transition for monolayer water above the room temperature, and provide a microscopic understanding which will have important implications for other nanofludic systems as well.

Item Type:	Journal Article
Publication:	LANGMUIR
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belong to AMER CHEMICAL SOC
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	29 Oct 2018 15:31
Last Modified:	29 Oct 2018 15:31
URI:	http://eprints.iisc.ac.in/id/eprint/60988

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