In this paper, we study the interfacial friction of water at graphitic interfaces with various topologies, between planar graphene sheets, inside and outside carbon nanotubes, goal to disentangle confinement curvature effects on friction. We show that coefficient exhibits a strong dependence; while is independent for slab, it decreases nanotube radius inside, but increases outside. As paradigm found vanish below threshold diameter armchair nanotubes. Using statistical description friction,...

Friction is one of the main sources dissipation at liquid water/solid interfaces. Despite recent progress, a detailed understanding friction in connection with structure and energetics solid surface lacking. Here we show for first time that \textit{ab initio} molecular dynamics can be used to unravel between nanoscale water contact graphene hexagonal boron nitride. We find whilst interface presents very similar two sheets, coefficient on nitride $\approx 3$ times larger than graphene. This...

The ubiquitous aquaporin channels are able to conduct water across cell membranes, combining the seemingly antagonist functions of a very high selectivity with remarkable permeability. Whereas molecular details obvious keys perform these tasks, overall efficiency transport in such nanopores is also strongly limited by viscous dissipation arising at connection between nanoconstriction and nearby bulk reservoirs. In this contribution, we focus on so-called entrance effects specifically examine...

We show, using extensive molecular dynamics simulations, that the of electric double layer (EDL) is very much dependent on wettability charged surface which EDL develops. For a wetting surface, dynamics, characterized by so-called zeta potential, mainly controlled properties and our work provides clear interpretation for traditionally introduced immobile Stern layer. In contrast, disappears nonwetting surfaces, potential deduced from electrokinetic effects considerably amplified existence...

In this contribution, we study situations in which nanoparticles a fluid are strongly heated, generating high heat fluxes. This situation is relevant to experiments locally heated by using selective absorption of radiation solid particles. We first for different types molecular interactions, models gold particles suspended octane and water. As already reported experiments, very fluxes temperature elevations (leading eventually particle destruction) can be observed such situations. show that...

Ion transport through nanopores drilled in thin membranes is central to numerous applications, including biosensing and ion selective membranes. This paper reports experiments, numerical calculations, theoretical predictions demonstrating an unexpectedly large ionic conduction solid-state nanopores, taking its origin anomalous entrance effects. In contrast naive expectations based on analogies with electric circuits, the surface conductance inside nanopore shown perturb three-dimensional...

In this work, we perform a theoretical study of liquid flow in graphitic nanopores different sizes and geometries. Molecular dynamics simulations liquids (water, decane, ethanol, OMCTS) carbon nanotubes (CNT) are shown to exhibit velocities 1–3 orders magnitude higher than those predicted from the continuum hydrodynamics framework no-slip boundary condition. These results support previous experimental findings obtained by several groups that reported exceptionally high rates CNT membranes....

Thermo-osmotic and related thermophoretic phenomena can be found in many situations from biology to colloid science, but the underlying molecular mechanisms remain largely unexplored. Using dynamics simulations, we measure thermo-osmosis coefficient by both mechanocaloric thermo-osmotic routes, for different solid-liquid interfacial energies. The simulations reveal, particular, crucial role of nanoscale hydrodynamics. For nonwetting surfaces, transport is amplified hydrodynamic slip at...

Nanofluidic systems show great promise for applications in energy conversion, where their performance can be enhanced by nanoscale liquid-solid slip. However, efficiency is also controlled surface charge, which known to reduce Combining molecular dynamics simulations and analytical developments, we the dramatic impact of charge distribution on slip-charge coupling. Homogeneously charged graphene exhibits a very favorable relation (rationalized with new theoretical model correcting some...

Hydrodynamic behavior at the vicinity of a confining wall is closely related to friction properties liquid/solid interface. Here we consider, using Molecular Dynamics simulations, electric contribution for charged surfaces, and induced modification hydrodynamic boundary condition boundary. The consequences liquid slippage electrokinetic phenomena, through coupling between hydrodynamics electrostatics within double layer, are explored. Strong amplification electro-osmotic effects revealed,...

The cooling dynamics of glass-embedded noble metal nanoparticles with diameters ranging from 4 to 26 nm were studied using ultrafast pump-probe spectroscopy. Measurements performed probing away the surface plasmon resonance avoid spurious effects due glass heating around particle. In these conditions, time-domain data reflect kinetics nanoparticle. Cooling are shown be controlled by both thermal resistance at nanoparticle-glass interface and heat diffusion in matrix. Moreover, conductances...

We study heat transfer from a heated nanoparticle into surrounding fluid using molecular dynamics simulations. show that the next to can be well above its boiling point without phase change. Under increasing temperature, flux saturates, which is in sharp contrast with case of flat interfaces, where critical observed followed by development vapor layer and drop. These differences are explained curvature-induced pressure close nanoparticle, inhibits boiling. When temperature much larger than...

Osmosis describes the flow of water across semipermeable membranes powered by chemical free energy extracted from salinity gradients. While osmosis can be expressed in simple terms via van 't Hoff ideal gas formula for osmotic pressure, it is a complex phenomenon taking its roots subtle interactions occurring at scale membrane nanopores. Here we use new opportunities offered nanofluidic systems to create an diode exhibiting asymmetric under reversal driving. We show that surface charge...

Among the numerous anomalies of water, acceleration dynamics under pressure is particularly puzzling. Whereas diffusivity anomaly observed in experiments has been reproduced several computer studies, parallel viscosity received less attention. Here we simulate and self-diffusion coefficient TIP4P/2005 water model over a broad temperature range. We reproduce experimental behavior find additional at negative pressure. The anomalous effect on dynamic properties becomes more pronounced upon...

In fluid transport across nanopores, there is a fundamental dissipation that arises from the connection between pore and macroscopic reservoirs. This entrance effect can hinder whole in certain situations, for short pores and/or highly slipping channels. this paper, we explore hydrodynamic permeability of hourglass shape nanopores using molecular dynamics (MD) simulations, with central size ranging several nanometers down to few Angströms. Surprisingly, find very good agreement MD results...

This article discusses the way standard description of capillary filling dynamics has to be modified account for liquid/solid slip in nanometric pores. It focuses, particular, on case a large length compared pore size. is shown that liquid viscosity does not play role, and flow only controlled by friction coefficient at wall. Moreover, Washburn regime, velocity depend tube radius. Finally, molecular simulations suggest this fails describe early stage carbon nanotubes water, since viscous...

This article describes the physics of superoleophobic surfaces, combining a recently developed free-energy approach and finite element modeling. We start by investigating peculiar wetting behavior such originating in their "re-entrant" geometry, discussing specific mechanism for "filling transition", leading to loss superoleophobicity. then focus on friction properties, establish an important condition use as super-lubricating surfaces. new insight into underlying mechanisms...

Following our recent theoretical prediction of the giant thermo-osmotic response water–graphene interface, we explore practical implementation waste heat harvesting with carbon-based membranes, focusing on model membranes carbon nanotubes (CNT). To that aim, combine molecular dynamics simulations and an analytical considering details hydrodynamics in membrane at tube entrances. The simulation results match quantitatively, highlighting need to take into account both thermodynamics predict...

This work revisits capillary filling dynamics in the regime of nanometric to subnanometric channels. Using molecular simulations water carbon nanotubes, we show that for tube radii below one nanometer, both velocity and Jurin rise vary nonmonotonically with radius. Strikingly, fixed chemical surface properties, this leads confinement-induced reversal wettability from hydrophilic hydrophobic specific values By comparing a model liquid metal, these effects are not water. complementary data...

Despite relevance to water purification and renewable energy conversion membranes, the molecular mechanisms underlying slip are poorly understood. We disentangle static dynamical origin of slippage on graphene, hBN MoS2 by means large-scale ab initio dynamics. Accounting for role electronic structure interface is essential determine that slips five eleven times faster graphene compared MoS2, respectively. Intricate changes in landscape as well density correlations fluid provide,...

Osmotic transport in nanoconfined aqueous electrolytes provides alternative venues for water desalination and "blue energy" harvesting. The osmotic response of nanofluidic systems is controlled by the interfacial structure electrolyte solutions so-called electrical double layer (EDL), but a molecular-level picture EDL to large extent still lacking. Particularly, role electronic has not been considered description electrolyte/surface interactions. Here, we report enhanced sampling simulations...

Defects are inevitably present in nanofluidic systems, yet the role they play transport remains poorly understood. Here, we report ab initio molecular dynamics (AIMD) simulations of friction liquid water on defective graphene and boron nitride sheets. We show that dissociates at certain defects these "reactive" lead to much larger than "nonreactive" which molecules remain intact. Furthermore, find is extremely sensitive chemical structure reactive number hydrogen bonds can partake with...

During the last few decades, many experimental and numerical studies have tried to understand special dynamics of water at low temperatures by measuring structural relaxation times or shear viscosity, but their conclusions strongly depended on chosen observable range considered. Moreover, recent work [J. Chem. Phys. 2013, 138, 12A526] showed that viscosity could decouple temperature in a model binary mixture, raising questions equivalence study supercooled water. Here we used molecular...