Observation of Water Confined in Nanometer Channels of Closed Carbon Nanotubes

Naguib, Nevin; Ye, Haihui; Gogotsi, Yury; Yazıcıoğlu, Almıla G.; Megaridis, Constantine M.; Yoshimura, Masahiro

doi:10.1021/nl0484907

Cited by 244 publications

(211 citation statements)

References 36 publications

(80 reference statements)

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“…Recent investigations have increased our understanding of confined water, showing that, in nanoscopic proportions, many water properties differ drastically from those of bulk water [10,11,12]. In particular, an excellent model is water confined in carbon nanotubes, which have been adopted in many previous studies [13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Among these interesting investigations, Koga et al investigated water inside single-walled carbon nanotubes (SWCNTs) of diameter 1.1∼1.4 nm and found that water forms ice nanotubes composed by a rolled square ice sheet [14,15,16].…”

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confidence: 99%

Ferroelectric Ordering in Ice Nanotubes Confined in Carbon Nanotubes

Luo

Zhou

et al. 2008

Nano Lett.

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We report that ice nanotubes with odd number of side faces inside carbon nanotubes exhibit spontaneous electric polarization along its axis direction by using molecular dynamics simulations. The mechanism of this nanoscale quasi-one-dimensional ferroelectricity is due to low dimensional confinement and the orientational order of hydrogen bonds. These ferroelectric fiber structural materials are different from traditional perovskite structural bulk materials. 85.35.Kt, 61.46.Fg, 68.08.De Whether ferroelectric ice exists is a question that has long fascinated researchers [1,2,3,4]. Although one water molecule has a significant dipole moment, normal hexagonal ice Ih does not possess ferroelectricity and it is very difficult to get an ice phase even with a weak whole polarization. Several year ago, the ferroelectricity of ice films grown on ultra-clean platinum was detected, although only a small proportion (0.2%) of the molecules are aligned [5,6]. Most recently, Fukazawa et al. have succeeded in making Ice XI in the laboratory and suggests existence of ferroelectric ice in the universe [7].Confinement of matter on the nanometer scale can induce phase transitions not seen in bulk systems [8,9]. In biology as well as in natural and synthetic materials, water is often tucked away in tiny crevices inside proteins or in porous materials. Therefore, water confined in nanoscale quasi-one-dimensional (Q1D) channels is of great interest to biology, geology, and materials science. Recent investigations have increased our understanding of confined water, showing that, in nanoscopic proportions, many water properties differ drastically from those of bulk water [10,11,12]. In particular, an excellent model is water confined in carbon nanotubes, which have been adopted in many previous studies [13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Among these interesting investigations, Koga et al. investigated water inside single-walled carbon nanotubes (SWCNTs) of diameter 1.1∼1.4 nm and found that water forms ice nanotubes composed by a rolled square ice sheet [14,15,16]. Recent neutron scattering studies, combined with molecular dynamics (MD) simulations, revealed that water in SWCNTs of diameter 1.4 nm forms a core-shell structure, in which the square ice sheet described by Koga et al. is coupled with a chainlike configuration at the center of the shell [27,28].Recently, investigations of nanoscale ferroelectric materials are very active due to its potential application [29,30,31]. Because of its particular structures, the ice nanotubes inside SWCNTs may exhibit ferroelectricity. * Electronic address: jdong@nju.edu.cnIn this paper, we report that ice nanotubes with odd number of side faces inside SWCNTs exhibit spontaneous electric polarization along its axis direction by using MD simulations. The origin of ferroelectricity of these ice nanotubes is due to the strong direction preferred hydrogen-bonds between water molecules and the Q1D confinement inside SWCNTs, which is different from traditional ferroelectric bulk materials, ...

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confidence: 99%

Ferroelectric Ordering in Ice Nanotubes Confined in Carbon Nanotubes

Luo

Zhou

et al. 2008

Nano Lett.

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“…However, studying the structural dynamics of nanodroplets is experimentally challenging because one needs to be able to externally induce the movement and be able to image the subsequent dynamic process of nanoscale droplets. Although atomic force microscope probes have measured the interfacial forces between liquids (18) and scanning transmission electron microscopy (TEM) has imaged small numbers of static water molecules confined in carbon nanotubes (19), these approaches fail to directly relate structure and dynamics of nanoscopic liquids. The ability to externally induce the movement and directly study the motion of model nanodroplets in contact with substrate interface may provide an insight to dynamic properties of interfacial water by experimentally complementing theoretical simulations.…”

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confidence: 99%

Direct observation of stick-slip movements of water nanodroplets induced by an electron beam

Mirsaidov

Zheng

Bhattacharya

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

108

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Dynamics of the first few nanometers of water at the interface are encountered in a wide range of physical, chemical, and biological phenomena. A simple but critical question is whether interfacial forces at these nanoscale dimensions affect an externally induced movement of a water droplet on a surface. At the bulk-scale water droplets spread on a hydrophilic surface and slip on a nonwetting, hydrophobic surface. Here we report the experimental description of the electron beam-induced dynamics of nanoscale water droplets by direct imaging the translocation of 10-to 80-nm-diameter water nanodroplets by transmission electron microscopy. These nanodroplets move on a hydrophilic surface not by a smooth flow but by a series of stick-slip steps. We observe that each step is preceded by a unique characteristic deformation of the nanodroplet into a toroidal shape induced by the electron beam. We propose that this beam-induced change in shape increases the surface free energy of the nanodroplet that drives its transition from stick to slip state. Although much is known about the movement of bulk water, most of what is known about interfacial water results from modeling and computational simulations (9, 10). Nanometer-diameter water droplets, because of their high surface-to-volume ratio and small number of molecules, present an ideal system for theoretical explorations of interfacial water dynamics induced by external forces. Such studies describe how external driving forces imposed by thermal (11), chemical (12), and topographic gradients (13) can lead to motion of nanometer-diameter droplets, and local fluctuations may result in the breakup of liquid nanojets (14). These theories imply that perturbations, either from external physical forces or chemical nonuniformities are coupled to dynamics of a nanodroplet through changes in shape and thus causing translocation of nanometer size droplets. Interestingly, very recent simulations also predict that nanometer-diameter water droplets will slip on hydrophilic surfaces (15) similar to those on hydrophobic surfaces (16,17). However, studying the structural dynamics of nanodroplets is experimentally challenging because one needs to be able to externally induce the movement and be able to image the subsequent dynamic process of nanoscale droplets. Although atomic force microscope probes have measured the interfacial forces between liquids (18) and scanning transmission electron microscopy (TEM) has imaged small numbers of static water molecules confined in carbon nanotubes (19), these approaches fail to directly relate structure and dynamics of nanoscopic liquids. The ability to externally induce the movement and directly study the motion of model nanodroplets in contact with substrate interface may provide an insight to dynamic properties of interfacial water by experimentally complementing theoretical simulations. Such studies will be critical in the design of materials tailored to the adhesion and flow of liquids at the interface (20, 21).Hydrodynamic slip of water that re...

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“…Simulations revealed that DNA molecules enter CNT spontaneously with the aid of van der Waals and hydrophobic interaction forces 47 and the translocation events can be driven by an electric field. 45 So far, experimental studies using nuclear magnetic resonance (NMR), 48 x-ray diffraction (XRD), 49 IR spectroscopy, 50 transmission electron microscope (TEM) 51 and scanning electron microscope (SEM) 52 have confirmed that water could enter and form ordered structures in SWCNTs or MWCNTs. More direct transport measurements are finished by using a CNT membrane, which consists of millions of carbon nanotubes in parallel.…”

Section: Carbon Nanotube Based Nanopore/ Nanochannel Devicesmentioning

confidence: 99%

“…98,99 Microscopically the chemical potential of water is lower inside the SWCNT than in the bulk, 43 and water can be transported at many thousand times the speed possible with classical Poiseulle flow. 43,53,54,100 Internal wetting of CNTs has been verified by transmission electron microscopy (TEM) 101 and a number of spectroscopy methods, [102][103][104][105][106][107] showing that water is ordered inside a CNT. The transport of water, ions and small molecules through CNTs has also been studied experimentally using membranes consisting of billions of carbon nanotubes in parallel.…”

Section: Introductionmentioning

confidence: 99%