Nanofluidic transporter

Mapping of transport parameters in complex pore spaces is of interest for many respects. Apart from classical porous materials such as rock, brick, paper and tissue, one can think of objects used in microsystem technology. Recent developments such as lab-on-a-chip devices require detailed knowledge of transport properties. More detailed information can be found in new journals such as Lab on a Chip [1] and Microfluidics and Nanofluidics [2], for example, devoted especially to this subject. Electrokinetic effects in microscopic pore spaces are discussed in Ref. [3]. 

Nanofluids are solid nanoparticles or nanofibers in suspension in a base fluid. To be qualified as nanofluid it is generally agreed that at least one size of the solid particle be less than 100 mn. Various industries such as transportation, electronics, food, medical industries require efficient heat transfer fluids to either evacuate or transfer heat by means of a flowing fluid. Especially with the miniaturization in electronic equipments, the need for heat evacuation has become more important in order to ensure proper working conditions for these elements. Thus, new strategies, such as the use of new, more conductive fluids are needed. Most of the fluids used for this purpose are generally poor heat conductors compared to solids (Fig. 1). 

Z.L. Wang, D.W. Tang, S. Liu, X.H. Zheng and N. Araki, Thermal-conductivity and thermal-drffusivity measurements of nanofluids by 3t method and mechanism analysis of heat transport, Int. J. Thermophys., 28, 1255-1268... 

J.A. Eastman, S.R. Phillpot, S.U.S. Choi and P. Kebhnski, Thermal transport in nanofluids. Annual Review of Materials Research, 34, 219-246 (2004). 

P. Keblinski, J.A. Eastman and D.G. Cahill, Nanofluids for thermal transport,... 

Wu Z, Nguyen N (2005) Convective-diffusive transport in parallel lamination micromixers. Microfluid Nanofluid 1(3) 208-217... 

Nicholls, D. et al., Water Transport Through (7,7) Carbon Nanotubes of Different Lengths using Molecular Dynamics, Microfluidics and Nanofluidics. 2012, 1-4, 257-264. 

Plecis, A., Schoch, R. B., and Renaud, P., Ionic transport phenomena in nanofluidics experimental and theoretical study of the exclusion-enrichment effect on a chip. Nano Letters, 5,1147-1155, 2005. 

As described earlier, azobenzene-functionalized nanoporous silica films exhibit dynamic photocontrol of their pore size, which in turn enables photoregulation of mass transport through the film. Their potential applications in nanofluidic devices, nanovalves, nanogates, smart gas masks, membrane separation, and controlled release can be anticipated. 

It is well-known that implicit solvent models use both discrete and continuum representations of molecular systems to reduce the number of degrees of freedom this philosophy and methodology of implicit solvent models can be extended to more general multiscale formulations. A variety of DG-based multiscale models have been introduced in an earlier paper of Wei [74]. Theory for the differential geometry of surfaces provides a natural means to separate the microscopic solute domain from the macroscopic solvent domain so that appropriate physical laws are applied to applicable domains. This portion of the chapter focuses specifically on the extension of the equilibrium electrostatics models described above to nonequilibrium transport problems that are relevant to a variety of chemical and biological S5 ems, such as molecular motors, ion channels, fuel cells, and nanofluidics, with chemically or biologically relevant behavior that occurs far from equilibrium [74-76]. 

The fast development of nanotechnology will lead to the emergence of nanofluidic technology. It is expected that the transport of irais and macromolecules and the cmitrol of liquid in nanofluidic channels and structures will stfll likely involve the use of an electrical field. This wfll open a completely new territoiy for nanofluidic-based electroldnetic phenomena which wfll be the main focus of the next decade of research. 

Stein D, Kruithof M, Dekker C (2004) Surface-charge-govemed ion transport in nanofluidic channels. Phys Rev Lett 93(3) 035901-l-035901-4... 

Das S, Das T, Oiakraborty S (2006) Modeling of coupled momentum, heat and solute Transport during DNA hybridization in a microchannel in presence of electro-osmotic effects and axial pressure gradients. Microfluid Nanofluid 2 37 9... 

The major application of DC electroosmotic flow in micro- and nanofluidics continues to be as a general transport mechanism in lab-on-chip-type devices. Specihc applications along these lines are too numerous to mention here, and thus, interested readers should consult any one of a number of recent review articles (e.g., Erickson et al. [6]) for more details. Rather we... 

The motion of electrically charged particles or molecules in a stationary medium under the influence of an electric field is called electrophoresis. In such transport the electric force is applied through a potential difference between electrodes. Selective use of the Lorentz force by applying a magnetic field can also induce such movement. Electrophoresis and electroosmosis are two key modaUties of electrokinetic transport which are very useful in micro- and nanofluidics for a variety of apphcations including biomedical (bio-NEMS, etc.), fuel cell, and micro total analysis systems (/r-TASs). In electroosmosis the bulk fluid moves due to the existence of a charged double layer at the solid-hquid interface. While one-dimensional electrophoresis is more commonly used, two-dimensional electrophoresis may also become a useful tool for the separation of gel proteins based on isoelectric property. 

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