Nano continua

B. Processes in Nano Continua, Discontinua, and Spaces of Interactions. 7... 

FIGURE 1.1 Bonded surface nano continua 0 — bulk material (volume continuum), 1 — interface, 2 — bonded surface continuum, 3 — external space of interaction, 4 — condensed adsorbed layer, 5 — new external space. 

Free nano continua or discontinua can be defined, also, as surface, line, and point elements, and as their combinations. Free surface elements are ideally composed of two nanolayers placed symmetrically each other (Figure 1.6). Such structures are ideal membranes and can be composed of solid materials, liquids, and even gasses. Ideal membranes exist in nature, e.g., bilipide cell membranes and black surfactant bubbles (Figure 1.7a and b). It is visible that both membranes are composed of only two molecular layers of asymmetric surface-active molecules, with hydrophilic ends placed outward (cell membranes) or inward (surfactant bubbles). Ideal membranes, composed... 

Basically, there are four kinds of physical or chemical processes in nano continua, discontinua, and spaces of interactions (1) processes in the nanospace over surface, line, or point elements (2) processes in the nanospaces inside surface, hne, and point elements (3) barrier processes — mass and energy transfer processes, with or without physical and chemical transformations, through internal and external nanospaces (4) membrane processes — mass and energy transport processes through membranes (double gas, hquid, and sohd surface, hne and point elements). Membrane processes are presented in Figure 1.13. 

Fig. 1. Comparison of pico-second (black) and nano-second (gray) spectra from a faceted and polished aquamarine. Note that the nanosecond spectrum has more peaks (from more elements) and far less continuum than the pico-second spectrum.

The extension of continuum models to complex environments is further analyzed by Ferrarini and Corni Frediani, respectively. In the first contribution the use of PCM models in anisotropic dielectric media such as liquid crystals is presented in relation to the calculation of response properties and spectroscopies. In the second contribution, PCM formulations to account for gas-liquid or liquid-liquid interfaces, as well for the presence of a meso- or nano-scopic metal body, are presented. In the case of molecular systems close to metal bodies, particular attention is devoted to the description of the surface enhanced effects on their spectroscopic properties. 

Odegard, Gregory M., and Langley Research Center. Equivalent-Continuum Modeling of Nano-Structured Materials. NASA Technical Memorandum, NASA/TM-2001-210863. Hampton, Va. National Aeronautics and Space Administration Langley Research Center available from NASA Center for AeroSpace Information (CASI), 2001. 

Consequently, the following four components were selected to prepare the photoresponsive emulsion system equal volumes of n-dodecane and 0.3 M NaNOs aqueous solution, the C12E4 surfactant, and an azobenzene-modified poly(acrylate). C12E4 is known to stabilize direct and inverse emulsions below and above the so-called phase inversion temperature (PIT here 24°C), respectively. Emulsions are unstable in the vicinity of the PIT, a temperature domain corresponding to the CTR of the light-responsive system. Emulsions made of equal oil and water volumes are directly below the PIT (and display a high electric conductivity because of the water continuum), but inverse (and of low conductivity) above the PIT (Khoukh et al., 2005). 

In Odegard s study [48], a method has been presented for finking atomistic simulations of nano-structured materials to continuum models of tfie corresponding bulk material. For a polymer composite system reinforced with SWCNTs, the method provides the steps whereby the nanotube, the local polymer near the nanotube, and the nanotube/ polymer interface can be modeled as an effective continuum fiber by using an equivalent-continuum model. The effective fiber retains the local molecular stractuie and bonding information, as defined by MD, and serves as a means for finking tfie eqniv-alent-continuum and micromechanics models. The micromechanics method is then available for the prediction of bulk mechanical properties of SWCNT/polymer com-... 

This method has been proposed for developing structure-property relationships of nano-structured materials and works as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with equivalent-continuum models. It has been shown that this substitution may be accomplished by equating the molecular potential energy of a nano-structured material with the strain energy of representative truss and continmrm models. 

TABLE 9.3 Nano-scale Continuum Methods for Prediction Young Modulus of CNT... 

TABLE 9.6 Nano-scale Continuum Simulation of CNT Buckling... 

TABLE 9.9 Nano-scale Continuum Modeling Simulation for Prediction Vibration Properties of CNTs... 

The study of fluid behavior in nano-confinement is a relatively new research arena. The ratio of surface area to volume becomes extremely large at such small scales in which the nondimensional Reynolds number Re is also typically low (<1) and the flow remains laminar. Diaguji et al. [4] mention that, except for steric interactions, intermolecular interactions like van der Waals force and electrostatic force can be modeled as continua. Specifically, the continuum dynanfics is an adequate description of liquid transport for length scales higher than 5 nm. In that context we... 

Nie XB, Chen SY, E WN, Robbins M (2004) A continuum and molecular dynamics hybrid method for micro and nano-fluid flow. J Fluid Mech 500 55-64... 

Part II continues with a section on various approaches and transitions. Chapter 6 covers polymer networks and transitions from nano- to macroscale by Plavsic. The following chapter is on the atomic scale imaging of oscillation and chemical waves at catalytic surface reactions by Elokhin and Gorodetskii. Then next chapter relates the characterization of catalysts by means of an oscillatory reaction written by Kolar-Anic, Anic, and Cupic. Then Dugic, Rakovic, and Plavsic address polymer conformational stability and transitions based on a quantum decoherence theory approach. Chapter 10 of this section, by Jaric and Kuzmanovic, presents a perspective of the physics of interfaces from a standpoint of continuum physics. 

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