Anisotropic interchain interactions

However, in all these calculations, the conjugated chains bear H atoms only. As bulkier side groups are introduced, the overall interchain interaction decreases and it becomes more anisotropic. If chains form stacks, relatively strong two-dimensional coupling will persist and may still have consequences similar to those of three-dimensional coupling. The question remains open. But substituted CPs are generally even more disordered than the simple ones, and we shall see now that disorder will then have more important consequences than the details of interchain interaction. 

The role of anisotropy and interchain interaction has been identified through dc and ac conductivity of stretch films, Kramers-Kronig analysis of reflectance on stretched films, anisotropic microwave frequency conductivity [44,52] and muon spin relaxation [62]. The role of interaction of spin of interstitial dopants with the conduction electrons at low temperatures has recently been explored by Y.W. Park and coworkers [63]. 

Vibrational modes perpendicular to the chain backbone arc only weakly coupled across neighboring chains by the various types of nonbonded interchain interactions. Heat transfer via backbone vibrations is therefore much more effective than heat transfer via vibrational modes perpendicular to the backbone. X is therefore a locally anisotropic property, as defined in Section 2.D. It is necessary to separate the connectivity indices into backbone and side group components because of this local anisotropy. 

Lyotropic LCPs are polymers whose solutions exhibit liquid crystallinity, that is, anisotropic domains in a fluid system, over a characteristic range of concentrations. In more concentrated solutions the system may be multiphasic and contain crystalline particles, amorphous gel particles and anisotropic solution coexisting with one another. Upon dilution, the anisotropic liquid crystalline solution turns biphasic, where anisotropic and isotropic solutions of the same polymer in the same solvent coexist. Upon further dilution, the solution becomes fully isotropic. Polymers that exhibit lyotropic mesomorp-hicity are either stiff-backbone polymers with strong interchain interaction in the absence of solvent or polymers whose backbones are so extended and rigid that, upon breakup of their crystalline order by the addition of some solvent, the stiff polymer chains retain substantial measure of parallel alignment to remain in mobile anisotropic domains. 

The achievement of high performance polymers with electrical and mechanical properties that approach intrinsic values will provide the opportunity to explore the intrinsic mechanisms of transport. For example, the study of the temperature dependence, pressure dependence, etc of phonon scattering in quasi-one-dimensional (quasi-id) metals with sufficient interchain interaction to avoid Id localization will surely be of interest. On the other hand, in the disordered conductor limit, hopping processes in anisotropic... 

In the previous section, we reported PMP derivatives bearing chiral side chains having a helicene-like helical structure through intrachain 7r-electron overlap interactions, which lead to a self-assembled whisker morphology due to interchain van der Waals interactions. However, each whisker of the PMP derivative is still randomly oriented, even if it has a self-assembled structure. It is therefore desirable to align the PMP derivative to construct a higher-ordered hierarchical structure and also to evolve an anisotropic nature in its potentially profound op-toelectrical properties. 

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