Multidimensional nanostructures

Design and fabrication of multidimensional nanostructures have been discussed for metals and ceramics in the previous chapters and most of the fabrication methods introduced earlier can be transferred to polymeric and composite systems. Generally, polymeric and composite nanostructures of different dimensions from 0-D (e.g., nanoparticles, nanodots) to 3-D (nanoscaffolds) can be fabricated by nanopattem-ing techniques, colloidal processes, electrospinning, physical and chemical vapor depositions, porogen strategy, self-assembly, and so on. These fabrication techniques discussed in the previous chapters are transferrable for preparing nanopolymers and... 

In practical application to common isotropic polymer materials the IDF frequently exhibits very broad distributions of domain thicknesses. At the same time fits of the IDF curve to the well-known models for the arrangement of domains (cf. Sect. 8.7) are not satisfactory, indicating that the existing nanostructure is more complex. In this case one may either tit a more complex model85 on the expense of significance, or one may switch to the study of anisotropic materials and display their nanostructure in a multidimensional representation, the multidimensional CDF. Complex domain topology is more clearly displayed in the CDF than in the IDF. The CDF method is presented in Sect. 8.5.5. 

Computational methods combined with a novel approach in the application of scattering physics were recently employed by Barbi et al. in a synchrotron SAXS study of the nanostructure of Nafion as a function of mechanical load. A new method of multidimensional chord-distribution function (CDF) analysis was used to visualize the multiphase nano-... 

Chernyak V, Zhang WM, Mukamel S. Multidimensional femtosecond spectroscopies of molecular aggregates and semiconductor nanostructures The nonlinear exciton equation. J Chem Phys 1998 109 9587-9601. 

Molecular mechanics has been used extensively to investigate the structures and mechanical properties of CNTs. By employing this technique, thermodjmamically stable structures for molecules and nanostructures can be obtained as minimum energy points on the multidimensional surface that represents the potential energy as a function of the atomic coordinates. In this section we review some previous studies involving molecular mechanics, which are especially relevant to our own work directed at the elucidation of factors that control the thermodynamics of polymer-CNT composites. 

Philippe, L. Kacem, N. Michler, J. Electrochemical deposition of metals inside high aspect ratio nanoelectrode array Analytical current expression and multidimensional kinetic model for cobalt nanostructure synthesis. J. Phys. Chem. C2007, 111, 5229-5235. 

McKelvey, K. O Connell, M. A. Unwin, P. R. 2013. Meniscus confined fabrication of multidimensional conducting polymer nanostructures with scanning electrochemical cell microscopy (SECCM). Chem. Commun., 49, 2986-2988. 

Multidimensional chord distribution functions [13, 14] (CDF) visualize the nanostructure of the studied materials and its evolution in real space. Figs. 4.8, 4.9, and 4.10. The general course of the peak intensities in the CDFs is identical to the development observed in the SAXS patterns. The materials exhibit an initial increase of peak intensities that is followed by a decrease for higher strain. 

This is the first step towards a multidimensional real-space nanostructure analysis of SAXS data with fiber symmetry, because it is related to the 2D correlation function in the representative plane of the real space,... 

For anisotropic samples, such as thermoplastic elastomers showing uniaxial orientation, the analysis of the longitudinal structure gives only a fraction of the total information concerning the nanostructure topology. By analogy with the IDF concept, the complete information should be displayed in a multidimensional function that maps the distances between all the domain surfaces. 

Figure 19. Nanostructure revealed in the multidimensional CDF, z ri2,r3) (-50 nm < r]2,r3 < 50 nm), as computed from SAXS. Water-swollen 80PTMO/PA12 film cast from n-butanol, at elongation e = 2. The draw direction is indicated, (a) CDF viewed from the top (b) CDF turned upside down...

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