Nano-structured fluid

If the local structure formation discussed in this chapter is not specific to bmimX ILs but applies to ILs in general, ILs may not be genuine liquids in the conventional sense. They might be better called nano-structured fluid or crystal liquid. They may form a new meso-phase that is distinct from the liquid... 

Biomaterials, Synthesis, Fabrication, and Applications Bioreactors Distillation electrochemical Engineering Fluid Dynamics Membrane Structure Membranes, Synthetic (Chemistry) Molecular Hydrodynamics Nano-structured Materials, Chemistry of Pharmaceuticals, Controlled Release of Solvent Extraction Wastewater Treatment and Water Reclamation... 

Many experiments and molecular simulations of the freezing of fluids confined in nanoporous solids have been reported [1]. This effort is devoted to the understanding of the effect of confinement, surface forces, and reduced dimensionality on the thermodynamics of fluids. These works are also of practical interest for applications involving confined systems (lubrication in nanotechnologies, synthesis of nano-structured materials, phase separation, etc). Beside the abundant literature for pure fluids in nanopores, few studies [2-7] have focused on the freezing of confined mixtures. As in the case of pure substances, the pore width H and the ratio of the wall/fluid to the fluid/fluid interaetions (parameter a [8]), play an important role in the phase behavior of the mixture. The ratio of the wall/fluid interaction for the two species is also a key parameter in describing freezing of these systems. 

Abstract The electrostatic Layer-by-Layer (LbL) technique allows the fabrication of polyelectrolyte multilayers that can be considered as a special type of interpolyelectrolyte complexes supported by a template (fluid or soUd). The main characteristic that confers special interest to these interpolyelectrolyte complexes is the simplicity and versatility of the method used for their fabrication, although in some cases this may hide the complex influence of the different physico-chemical variables. The possibility to change ionic strength, pH, temperature, etc. and/or the composition makes possible to control the properties and structure of these systems. Furthermore, the compositional and structural richness of these systems opens multiple possibilities for the fabrication of nano-structured materials with tailored properties for numerous applications (from optical to nanomedical devices). This chapter deal with the physico-chemical background of the fabrication of supramolecular films by the LbL method as well as the key properties that should be managed in order to obtain functional materials following this approach. 

A number of methods exist to simulate dispersed multiphase flows. When choosing a particular simulation method, it is important to consider first the relevant length scales. The most obvious length scales are, from large to small, the dimensions of the confinement (equipment dimensions), the dimensions of the discrete elements (particles, bubbles, or droplets), and the mean free path of the molecules in the continuous fluid phase. The molecular mean free path ranges firom less than a nanometer in a liquid to the order of 100 nm in a gas at ambient pressure. Discrete molecular effects such as Brownian forces and molecular slip conditions are therefore very important in nanofluidic and small microfluidic devices (Hadjiconstantinou, 2006). They are also very important for the dynamic behavior of nano (structured) particles in gas flows and colloidal particles suspended in a liquid. In these... 

TFL is an important sub-discipline of nano tribology. TFL in an ultra-thin clearance exists extensively in micro/nano components, integrated circuit (IC), micro-electromechanical system (MEMS), computer hard disks, etc. The impressive developments of these techniques present a challenge to develop a theory of TFL with an ordered structure at nano scale. In TFL modeling, two factors to be addressed are the microstructure of the fluids and the surface effects due to the very small clearance between two solid walls in relative motion [40]. 

The integrated DLS device provides an example of a measurement tool tailored to nano-scale structure determination in fluids, e.g., polymers induced to form specific assemblies in selective solvents. There is, however, a critical need to understand the behavior of polymers and other interfacial modifiers at the interface of immiscible fluids, such as surfactants in oil-water mixtures. Typical measurement methods used to determine the interfacial tension in such mixtures tend to be time-consuming and had been described as a major barrier to systematic surveys of variable space in libraries of interfacial modifiers. Critical information relating to the behavior of such mixtures, for example, in the effective removal of soil from clothing, would be available simply by measuring interfacial tension (ILT ) for immiscible solutions with different droplet sizes, a variable not accessible by drop-volume or pendant drop techniques [107]. 

In conclusion it was shown that the solid-state complexes formed by poly(L-arginine), poly(L-histidine) and poly(L-lysine) cations and retinoic acid can be prepared as films and nano-particles. The high content of retino-ate moieties, the absence of crystallinity and low particle sizes could make these complexes interesting as a new carrier for the delivery of retinoic acid, either transdermal or in body fluids. It may be speculated that supramolecu-lar structures such as the smectic A-like nano-particles of the tart-type pre-... 

Confined Complex Fluids. - Because of their important technological relevance, the study of alkanes and polymers under extreme confinement continues to gain popularity in the simulation community. The difficulty in making experimental measurements for nano-confined systems, and the lack of confirmed theoretical models for such systems, makes molecular simulation the ideal tool to explore thermodynamics, structure and transport at such scales. 

L K. Nielsen, A. Vishnyakov, K. Jorgensen, T. Bjornholm, and O.G. Mouritsen. Nano-meter-scale structure of fluid lipid membranes./. Phys. Con-dens. Matter, 2000, 12, 309-314. 

The definition of the term nanoparticles varies significantly depending on the scientific community where it is used. While in material sciences, the prefix nano is generally restricted to structures smaller than 10 nm or, at the most, 100 nm, the same term in pharmaceutical sciences may refer to particles with up to 1000 nm in diameter. However, when dealing with nanoparticles, there is general agreement on the phase state of the particles themselves which are supposed to be solid and dispersed in a continuous solid or fluid medium. In the following, we stick to a nomenclature that is common in pharmaceutical applications and has been proposed by Kreuter spherical nanoparticles with a compact solid structure are referred to as nanospheres, while hollow nanoparticles with a fluid content are named nanocapsules. 

The porous skeleton of activated carbon can be used as a template on which to construct other porous materials, for example, Si02, Ti02 and AI2O3. The oxide is first dissolved in supercritical CO2 (see Section 8.13) and then the activated carbon template is coated in the supercritical fluid. The carbon template is removed by treatment with oxygen plasma or by calcination in air at 870 K, leaving a nano-porous ( nano refers to the scale of the pore size) metal oxide with a macroporous structure that mimics that of the activated carbon template. 

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