The influence of water polarization on slip friction at charged interfaces.

The present study employs equilibrium molecular dynamics simulations to explore the potential mechanism for controlling friction by applying electrostatic fields in nanoconfined aqueous electrolytes. The slip friction coefficient demonstrates a gradual increase corresponding to the surface charge density for pure water and aqueous electrolytes, exhibiting a similar trend across both nanochannel walls. An expression is formulated to rationalize the observed slip friction behavior, describing the effect of the electric field on the slip friction coefficient.

Thermal transport in a defective pillared graphene network: insights from equilibrium molecular dynamics simulation.

Graphene-based hybrid nanostructures have great potential to be ideal candidates for developing tailored thermal transport materials. In this study, we perform equilibrium molecular dynamics simulations employing the Green-Kubo method to investigate the influence of topological defects in three-dimensional pillared graphene networks. Similar to single-layer graphene and carbon nanotubes, the thermal conductivity () of pillared graphene systems exhibits a strong correlation with the system size (), following a power-law relation ∼ , where ranges from 0.

Temperature-dependent differential capacitance of an ionic liquid-graphene-based supercapacitor.

One of the critical factors affecting the performance of supercapacitors is thermal management. The design of supercapacitors that operate across a broad temperature range and at high charge/discharge rates necessitates understanding the correlation of the molecular characteristics of the device (such as interfacial structure and inter-ionic and ion-electrode interactions) with its macroscopic properties. In this study, we use molecular dynamics (MD) simulations to investigate the influence of Joule heating on the structure and dynamics of the ionic liquid (IL)/graphite-based supercapacitors.

Use of Multiple Fluid Biomarkers for Predicting the Co-occurrence of Diabetes and Hypertension Using Machine Learning Approaches.

The co-existence of diabetes and hypertension can complicate and affect the management of these diseases. The early detection of these comorbidities can help in developing personalized preventive treatments and thereby, reduce the healthcare burden. The inclusion of readily available fluid biomarkers from different body fluids can be used as diagnostic tools and can facilitate in the designing of treatment strategies.

Effects of interfacial molecular mobility on thermal boundary conductance at solid-liquid interface.

The effects of interfacial molecular mobility on the thermal boundary conductance (TBC) across graphene-water and graphene-perfluorohexane interfaces were investigated using non-equilibrium molecular dynamics simulations. The molecular mobility was varied by equilibrating nanoconfined water and perfluorohexane at different temperatures. The long-chain molecules of perfluorohexane exhibited a prominent layered structure, indicating a low molecular mobility, over a wide temperature range between 200 and 450 K.

Modeling the effect of chirality on thermal transport in a pillared-graphene structure.

The anisotropic heat transport in graphene-CNT based materials provoked the development of three-dimensional pillared-graphene (PG) systems. In this study, we performed non-equilibrium molecular dynamics simulations to analyze PG thermal conductivity and thermal boundary conductance. For the first time, we have considered the influence of pillar chirality and the temperature effect on PG heat transport.

A data driven approach to model thermal boundary resistance from molecular dynamics simulations.

A new method is proposed to model the thermal boundary resistance (TBR) at the nanoscale, solid-liquid interface from macroscopic observables that characterize a nanoscale interface. We correlated the TBR with thermodynamic state variables, material properties, and geometric parameters to derive a generalized relationship with the help of data-driven heuristic algorithms. The results show that TBR can be expressed in terms of physical observables of the systems and material-specific parameters.

Nanoscale gas accumulation at solid-liquid interfaces: a molecular dynamics study.

The development of the interfacial gas enrichment layer at the solid-liquid interface is coupled with the stability of surface nanobubbles. Depending upon the concentration of gas molecules, solid-liquid-gas interaction strengths, and other thermodynamic parameters, gas molecules can take several different forms such as dense gas layer, bulk and surface nanobubble, and other gaseous domains. Using molecular dynamics simulations we study the characteristics of gas accumulation into a dense gas layer, surface nanobubble and local gas aggregation at the graphene-water interface with no pinning sites.

Effects of Electrostatic Interactions on Kapitza Resistance in Hexagonal Boron Nitride-Water Interfaces.

Electrostatic interactions in nanoscale systems can influence the heat transfer mechanism and interfacial properties. This study uses molecular dynamics simulations to investigate the impact of various electrostatic interactions on the Kapitza resistance () on a hexagonal boron nitride-water system. The Kapitza resistance at hexagonal boron nitride nanotube (hBNNT)-water interface reduces with an increase in diameter of the nanotube due to more aggregation of water molecules per unit surface area.

Hydrodynamic slip of alkali chloride solutions in uncharged graphene nanochannels.

Using non-equilibrium molecular dynamics simulations, we demonstrate the effect of concentration and alkali cation types (K, Na, and Li) on the hydrodynamic slip of aqueous alkali chloride solutions in an uncharged graphene nanochannel. We modeled the graphene-electrolyte interactions using the potential of Williams et al. [J.

Rotational dynamics of proteins in nanochannels: role of solvent's local viscosity.

Viscosity variation of solvent in local regions near a solid surface, be it a biological surface of a protein or an engineered surface of a nanoconfinement, is a direct consequence of intermolecular interactions between the solid body and the solvent. The current coarse-grained molecular dynamics study takes advantage of this phenomenon to investigate the anomaly in a solvated protein's rotational dynamics confined using a representative solid matrix. The concept of persistence time, the characteristic time of structural reordering in liquids, is used to compute the solvent's local viscosity.

Nanoconfinement Effects on the Kapitza Resistance at Water-CNT Interfaces.

The Kapitza resistance () at the water-carbon nanotube (CNT) interface, with water on the inside of the nanotube, was investigated using molecular dynamics simulations. We propose a new equilibrium molecular dynamics (EMD) method, also valid in the weak flow regime, to determine the Kapitza resistance in a cylindrical nanoconfinement system where nonequilibrium molecular dynamics (NEMD) methods are not suitable. The proposed method is independent of the correlation time compared to Green-Kubo-based methods, which only work in short correlation time intervals.

Variation of momentum accommodation coefficients with pressure drop in a nanochannel.

Accommodation coefficients (ACs) are the phenomenological parameters used to evaluate gas-wall interactions. The gas transport through a finite length nanochannel will confront the variation of properties along the length of the channel. A three-dimensional molecular dynamics simulation has been carried out to examine this streamwise inhomogeneity of flow characteristics in a nanochannel.

Kapitza resistance at water-graphene interfaces.

Heat transfer across fluid-solid interfaces in nanoconfinement has received significant attention due to its relevance in nanoscale systems. In this study, we investigate the Kapitza resistance at the water-graphene interface with the help of classical molecular dynamics simulation techniques in conjunction with our recently proposed equilibrium molecular dynamics (EMD) method [S. Alosious et al.

Thermal conductivity of graphene under biaxial strain: an analysis of spectral phonon properties.

Thermal transport in graphene is strongly influenced by strain. We investigate the influence of biaxial tensile strain on the thermal conductivity of zigzag and armchair graphene (AG and ZG) using non-equilibrium molecular dynamics simulations (NEMD). We observe that the thermal conductivity is significantly reduced under strain with a maximum reduction obtained at equi-biaxial strain.

Non-isothermal flow of an electrolyte in a charged nanochannel.

Electrokinetic flows are generally analyzed, assuming isothermal conditions even though such situations are hard to be achieved in practice. In this paper, the flow of a symmetric electrolyte in a charged nanochannel subjected to an axial temperature gradient is investigated using molecular dynamics simulations. We analyze the relative contribution of the Soret effect, the thermoelectric effect, and the double layer potential in the electrical double layer for various surface charges and temperature gradients.

The effect of temperature on water desalination through two-dimensional nanopores.

Two-dimensional (2D) materials such as graphene, molybdenum sulfide, and hexagonal boron nitride are widely studied for separation applications such as water desalination. Desalination across such 2D nanoporous membranes is largely influenced by the bulk transport properties of water, which are, in turn, sensitive to the operating temperature. However, there have been no studies on the effect of temperature on desalination through 2D nanopores.

Phonon coupling induced thermophoresis of water confined in a carbon nanotube.

The controlled transport of water through nanoscale devices is an important requirement in the design and development of various nanofluidic systems. Molecular dynamics simulations are performed to investigate the phonon coupling induced thermophoretic transport of water through a carbon nanotube (CNT). Phonon coupling is believed to have a significant role in the transport of heat at the liquid-solid interface.

Prediction of Kapitza resistance at fluid-solid interfaces.

Understanding the interfacial heat transfer and thermal resistance at an interface between two dissimilar materials is of great importance in the development of nanoscale systems. This paper introduces a new and reliable linear response method for calculating the interfacial thermal resistance or Kapitza resistance in fluid-solid interfaces with the use of equilibrium molecular dynamics (EMD) simulations. The theoretical predictions are validated against classical molecular dynamics (MD) simulations.

Effect of Hydrogen Bonds on the Dielectric Properties of Interfacial Water.

The dielectric constant for water is reduced under confinement. Although this phenomenon is well known, the underlying physical mechanism for the reduction is still in debate. In this work, we investigate the effect of the orientation of hydrogen bonds on the dielectric properties of confined water using molecular dynamics simulations.

Water flow in carbon nanotubes: the role of tube chirality.

We investigated the effects of the chirality of carbon nanotubes (CNTs) on water transport using molecular dynamics simulations. For the study, we considered CNTs with similar diameter and varying chiralities, obtained by altering the chiral indices (n,m) of the nanotubes. The tubes with an armchair (n = m) structure show the maximum streaming velocity, flux, flow rate enhancement and slip length, whereas the corresponding values are lower for chiral (n≠m) tubes, and are the lowest in zigzag (m = 0) CNTs.