Cross-linked polymers nanostructure materials

As it has been noted above, at present it is generally acknowledged [2], that macromolecular formations and polymer systems are always natural nanostructural systems in virtue of their structure features. In this connection the question of using this feature for polymeric materials properties and operating characteristics improvement arises. It is obvious enough that for structure-properties relationships receiving the quantitative nanostructural model of the indicated materials is necessary. It is also obvious that if the dependence of specific property on material structure state is unequivocal, then there will be quite sufficient modes to achieve this state. The cluster model of such state [3-5] is the most suitable for polymers amorphous state structure description. It has been shown, that this model basic structural element (cluster) is nanoparticles (nanocluster) (see Section 15.1). The cluster model was used successfully for cross-linked polymers structure and properties description [61]. Therefore, the authors of Ref [62] fulfilled nanostmetures regulation modes and of the latter influence on rarely cross-linked epoxy polymer properties study within the frameworks of the indicated model. 

The radiation technique is widely used for the production of nanostructured polymer-containing materials such as polymeric nanocomposites and nanogels (Sharif et al. 2007, Ulanski and Rosiak 1999). The radiation processing of these materials is accompanied by various radiation-induced processes (polymerization, cross-linking, degradation of polymeric chains, etc.) (Chmielewski et al. 2005). 

The inherent flexibility of the phosphazene structure leads to the development of advanced materials. A significant amount of work has been published using functionalized cyclotriphosphazenes to yield cyclomatrix-type polymers that have been fashioned into nanoparticles and other nanostructures. Papers have been previously published based on the chemistry of 4,4 -sulfonyldiphenol substituted cyclotriphosphazene (49). An idealized structure is shown. Typically, formation of the substituted trimer yields cross-links between trimer rings through the activity of the terminal hydroxyls. Techniques have been developed to control the polymerization of the these materials forming nanotubes, nanoparticles, and coatings for multi-walled carbon nanotubes, as shown below. 

The obtained patterned polymer surfaces can also be replicated by metal thermal evaporation to produce nanostructured metallic films with holes or asperities of controlled size, as illustrated in Fig. 11.10. After deposition of a sufficiently thick metal layer, the polymer layer can be cleaved or dissolved away. This procedure allows an efficient and precise control of the metallic surface structure, with possible applications in materials science and photonics. The roughness of polydimethylsiloxane (PDMS) surfaces can be tuned by this technique if the PDMS is treated while cross-linking, which may be of interest for microfluidic applications. We have also observed that substrates of poly(methyl methacrylate) (PMMA), PS in the form of colloidal spheres and bulk, and semiciystalline films of polyethylene (PE) are prrMie to be structured by this technique, evidencing the versatility and potential for its widespread use. It may find applications in many different scientific and technological fields like nanoUthography, microfluidics, or flexible electronics. 

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