External network formation

Level 3, external network formation, focuses on the customer through collaboration with selected partners. 

Throughout this chapter, predictions are made concerning the effect of external variables on the network structure evolution and these predictions are compared with experimental results. The predictions are based on branching theories. The purpose of this section is to outline the basis of present network formation theories and the underlying assumptions. 

Self-Associative Polymer Network. In self-associative polymer networks (often called one component systems), the hydrogen bonding recognition units that are covalently attached to the polymer backbone have an appreciable tendency for self-association, that is, self-dimerize, which leads to interchain cross-linking of the polymers. As a result, the system is inherently cross-linked and does not require any external cross-linking agents for network formation (Fig. 5.11a). Because the cross-linking is based on dimerization phenomena, to achieve effective... 

Supramolecular network formation can be switched on and off by an external stimmulus... 

The processing history of CNT composites plays a significant role in determining the final transport properties. Each composite production technique induces different network formations, and resultant percolation thresholds can vary widely. From the initial methods to produce conductive CNT-polymer composites, more elaborate methods have been reported that attempt to manipulate, or nanostructure, the formation of percolated CNT networks such that the resulting percolation threshold is reduced. Two approaches towards nano-structuring polymeric nanocomposites include external-in [top-down] and internal-out [bottom-up] approaches. The first approach is described by a direct patterning of nanoparticle... 

The formation of a 3D lattice does not need any external forces. It is due to van der Waals attraction forces and to repulsive hard-sphere interactions. These forces are isotropic, and the particle arrangement is achieved by increasing the density of the pseudo-crystal, which tends to have a close-packed structure. This imposes the arrangement in a hexagonal network of the monolayer. The growth in 3D could follow either an HC or FCC struc-... 

Two system-dependent interpretative pictures have been proposed to rationalize this percolative behavior. One attributes percolation to the formation of a bicontinuous structure [270,271], and the other it to the formation of very large, transient aggregates of reversed micelles [249,263,272], In both cases, percolation leads to the formation of a network (static or dynamic) extending over all the system and able to enhance mass, momentum, and charge transport through the system. This network could arise from an increase in the intermicellar interactions or for topological reasons. Then all the variations of external parameters, such as temperature and micellar concentration leading to an extensive intermicellar connectivity, are expected to induce percolation [273]. 

In absence of external salt, strong electrostatic interchain interactions exist in solution causing very large increase of the reduced viscosity and the formation of a pseudo electrostatic 3D network this was recently discussed [24], It implies the salt sensitivity of the viscosity which decreases when neutral salt is added due to a screening effect on the long range electrostatic repulsions. 

The chip is a standalone microsensor system that does not need any external measurement equipment for sensor control and readout. The sensor system chip has been connected to a computer via an f C-to-USB converter box, i.e., in this box is a microcontroller that translates the I C format coming from the chip into USB format for the computer or laptop. The power supply of the chip is also provided by the USB connection. The sensor system can be read out directly by a microcontroller and is, therefore, well suited for handheld devices or distributed sensor networks. 

In fact a liquid surface in the absence of external perturbations such as mechanical vibrations is perhaps the most smooth (disordered) surface that can be achieved by the action of gravity. Clearly, LB films could not be grown in the absence of gravity, e.g., in a Space Shuttle. In the case of water, the flat water/air interface has a roughness of 0.3 nm, a value determined by X-ray reflectivity measurements (Braslau et al, 1985). A further advantage of water is its relatively high surface tension yo. when compared to other liquids, which amounts to 72.8 mN m for pure water at RT. This value originates in the formation of a network of weak... 

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