Hydration behavior under confinement and in the presence of a cosolvent: an exploration based on molecular dynamics simulation

Abstract

Ever since the discovery of graphene sheets and carbon nanotubes (CNT) nearly seven decades ago, their potential applications have grown manifold; such ideas now include the construction of cheaper biosensors and nanofiltration devices. It has been observed from previous studies that the water molecules flow through hydrophobic confinement, by maintaining a single chain-like structure or making distinct layers depending upon the nanochannel dimensions. Our previous study reported the anomalous behavior of confined water up to a certain length of the nanotube in the presence of a cosolvent hexafluoro-2-propanol (HFIP). Our current work showcases the interplay between density deviation and the dynamical fluctuations of confined water molecules at different time points along with different length scales of the carbon nanotube in the presence or absence of the aforementioned cosolvent.

Graphical abstract

In this article we elaborate on the effect of cosolvent impurity within hydrophobic confinement of single-walled carbon nanotubes (SWCNT) of variable length scale; through density deviation-based entropic estimation coupled with dynamical fluctuation. The study lends important insight into hydration behavior inside nanoconfinement alongside the non-covalent surface functionalization of CNT.