Molecule-based networks

An induced dipole charge creates a relatively weak bonding of the H- -B type. 

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An interesting experiment on a DNA-based network embedded in a cast film had already been done by Okahata et al. in 1998 [49]. In this pioneering experiment the DNA molecules were embedded (with side groups) in a polymer matrix that was stretched between electrodes (see Fig. 12). It was found that the conductivity parallel to the stretching direction (along the DNA) was 4.5 orders of magnitude larger than the perpendicular conductivity. 

In a system based largely on self-assembly through mesogenic interactions such as the above example by Percec, it can also be beneficial to incorporate hydrogen bonding as well for an added element of organizational control. For instance, Frechet and coworkers demonstrated sequential, hierarchical self-assembly of various levels of order in a small molecule-based system which ultimately resulted in a hydrogen-bonded liquid crystalline network (Fig. 7.9) [53]. 

Ohesteom, L. and Larsson, K. Molecule Based Materials - the Structural Network Approach Elsevier Amsterdam, 2005. 

L. Ohrstrom, K. Larsson, Molecule-Based Materials The Structural Network Approach, Elsevier, Amsterdam, 2005. 

Fig. 6.1 Part of the structure of ice it consists of a three-dimensional network of hydrogen-bonded H2O molecules. (Based on L. Pauling (1960) The Nature of the Chemical Bond, Cornell University Press, Ithaca.)...

Molecule-based materials exhibiting cooperative physical properties constitute one of the most active areas of interest in contemporary materials chemistry and science. An attractive chemical feature of these materials is the synthetic versatility provided by molecular chemistry. From the point of view of the physical properties, molecule-based materials can exhibit the properties of interest usually associated with the inorganic network solids, " as for example, high DC metal-like electrical conductivity and superconductivity, ferromagnetism, and non-linear optical responses. ... 

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