Dendritic molecule display

Dendritic molecules (cascade molecules) are repetitively branched compounds. This collective term embraces the various dendrimers. The latter generally exhibit almost perfect structures and display properties characteristic of monodisperse compounds (see also Section 1.3). With regard to their molecular masses, dendrimers range from low-molecular to high-molecular chemistry. 

The structure and properties of water soluble dendrimers, such as 46, is, in itself, a very promising area of research due to their similarity with natural micellar systems. As can be seen from the two-dimensional representation of 46 the structure contains a hydrophobic inner core surrounded by a hydrophilic layer of carboxylate groups (Fig. 12). However these dendritic micelles differ from traditional micelles in that they are static, covalently bound structures instead of dynamic associations of individual molecules. A number of studies have exploited this unique feature of dendritic micelles in the design of novel recyclable solubilization and extraction systems that may find great application in the recovery of organic materials from aqueous solutions [84,86-88]. These studies have also shown that dendritic micelles can solubilize hydrophobic molecules in aqueous solution to the same, if not greater, extent than traditional SDS micelles. The advantages of these dendritic micelles are that they do not suffer from a critical micelle concentration and therefore display solvation ability at nanomolar... 

Dendrimers may be molecular in which they are made up entirely of covalent bonds and thus the molecule is a well-defined, large single molecule. This molecule may display interesting properties of interest to the supramolecular chemist, e.g. arising from the increasing density of linkages towards the edge of the molecule and the creation of void space in the interior. Alternatively they may be supramolecular with, for example, a number of dendritic arms linked via non-covalent interactions to a common core. 

A strategy to use renewable resource for PANl nanofibers was developed from a raw material, cardanol, which is an industrial waste and pollutant from the cashew nut industry. A new amphiphilic molecule, 4-[4-hydroxy-2-((Z)-pentadec-8-enyl) phenylazo] ben-zenesulfonic acid, was studied for cardanol and employed as a dopant to produce PANl nanomaterials with a variety of morphologies including microspheres and nanotubes besides linear and dendritic nanofibers (Anilkumar and Jayakannan, 2007). For the PANl nanofibers, they displayed 5 pm in length and 200 run in diameter (Fig. 3.3B). 

Due to their high molecular masses, macromolecular substances (polymers) show particular properties not observed for any other class of materials. In many cases, the chemical nature, the size, and the structure of these giant molecules result in excellent mechanical and technical properties. They can display very long linear chains, but also cyclic, branched, crosslinked, hyperbranched, and dendritic architectures as well. The thermoplastic behaviour or the possibility of crosslinking of polymeric molecules allow for convenient processing into manifold commodity products as plastics, synthetic rubber, films, fibres, and paints (Fig. 1.1). 

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