HATn Materials

Much work has been focused on the HATn materials (Scheme 1). Their electrical properties are typical of wide band-gap transparent columnar liquid crystals in general and can be considered as a model system. 

The HATn materials have no permanent dipoles in the ideal symmetric state, but surprisingly have a relatively large low frequency dielectric constant e (T) of the order 3 which varies only weakly with temperature [38]. 

HATn materials, electrical properties 782 ff He-Ne laser addressed devices 478 head-tail equivalence, antiferroelectrics 665 f heal capacity, OCB 450 Heck coupling, hydrocarbon cores 707 Heilmeier displays... 

Network-PIMs can adsorb phenol from aqueous solution. Hence, they can be used for the separation of organic compounds from the aqueous phase. This process can also be utilised for the separation of phenol from waste water. One such example is HATN-network-PIM, which can adsorb up to 5 mmol g . This material can also efficiently remove a low concentration of phenol from water. Another such example is PcCo-network-PIM. These network-PIMs behave like activated carbon. In contrast, PcCo-network-PIM cannot adsorb large dyes [e.g., Napthol Green B) like activated carbons. This distinct size exclusion effect is due to its small pore size. ... 

We start by reminding ourselves that columnar discotic liquid crystals are comprised of disordered stacks (1-dimensional fluids) of disc-shaped molecules arranged on a two-dimensional lattice (Fig. 1) [1]. This structure imparts novel properties to these materials from which applications are likely to stem. One such property is the transport of charge along the individual molecular stacks [2-7]. The separation between the aromatic cores in, for example, the hexa-alkoxytriphenylenes (HATn), the archetypal columnar discotic mesogen, is of the order of 0.35 nm, so that considerable overlap of n orbitals of adjacent aromatic rings is... 

It turns out, however, that the HATn have a very low intrinsic carrier concentration, owing to the large band-gap in these materials. They are therefore good insulators (Table 1) with high breakdown fields of 4 MV cm [9]. The mobility of an injected charge along the molecular columns (wires) is, however, fairly high [10-12]. 

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