Development in electrical and optical properties of organic materials by 3-D structural control using dendrimer as a command molecule.

驱动剂是定义明确的高度支化的三维化合物，具有大量的活性端基。此外，这些活性端基很容易与许多试剂反应，从而在表面形成具有不同官能度的树枝状大分子。因此，它们作为新的聚合物材料受到了人们的关注，它们的性质应该与线性聚合物有很大的不同。通常，由于高度支化的分子，树枝状大分子是无定形的。将液晶衍生物引入它们的端基，使它们具有液晶性质。通过外加磁场或电场可以实现液晶树枝状大分子的定向排列。我们合成了含偶氮苯和苯基萘衍生物的聚亚丙基亚胺树枝状大分子(第一代、第二代和第三代)，并对其相变行为、液晶结构、光异构化和载流子传输性能进行了研究。偶氮苯脱水剂表现为近晶A(SmA)…相越多，SMA/各向同性相变温度越高。室温下，在紫外光和可见光照射下，在氯仿溶液和薄膜中观察到顺反光异构化反应。在顺反光异构化过程中，薄膜中形成了一种同向异性排列。另外，在可见光照射下，可以在薄膜上形成光致表面浮雕。因此，可以通过偶氮苯树枝状大分子的表面浮雕和分子取向来制作衍射光栅。在室温下，外围含有苯基萘衍生物的树枝状大分子表现出近晶液晶性质。研究了树枝状大分子的相变、结构和载流子输运性质。它们在室温下的载流子迁移率为10^&lt；-3&gt；cm^&lt；2&gt；/vs(SmE相)。这些值与低分子液晶苯基萘衍生物的值相当。因此，树枝状大分子的主链可以避免结晶，并在室温下表现出高的载流子传输能力。此外，苯基萘树枝状大分子还在底物上形成同向异性结构。同向取向似乎更有利于垂直型晶体管的结构。较少

Drimers are well defined highly branched, three-dimensional compounds with a large number of reactive end groups. Moreover, these reactive end groups easily react with many reagents to give dendrimers with various functionalities on the surface. Thus, they are receiving interest as new polymeric materials whose properties should differ significantly from those of linear polymers. Generally, dendrimers are amorphous due to highly branched molecules. Introduction of liquid crystalline derivatives to their terminal groups gives them liquid crystalline nature. The liquid crystalline dendrimers can be aligned by applying external field such as magnetic or electric fields. We have synthesized poly (propyleneimine) dendrimers (1st, 2nd, and 3rd generation) having peripheral azobenzene and phenylnaphthalene derivatives, and examined the phase transition behavior, liquid crystalline structure, photoisomerization and carrier transport property. The azobenzene deindrimers exhibite smectic A (SmA) … More phase, and the SmA/isotropic phase transition temperature increases with increasing generation. Cis-trans photoisomerization was observed in the chloroform solution and film at room temperature under UV and visible light irradiation. During the cis-trans photoisomerization, a homeotropic alignment was formed in the film. In addition, the photoinduced surface relief could be formed on the films by irradiating visible light. Therefore, the diffraction grating can be made by surface relief and molecular alignment using azobenzene dendrimers The dendrimers having peripherally phenylnaphthalene derivatives exhibited smectic liquid Crystalline nature at room temperature. The phase transition, structures, and carrier transport property of the dendrimers have been examined. They exhibited the carrier mobility of 10^<-3>cm^<2>/Vs at room temperature (SmEphase). The values are equivalent to that of the low-molecular liquid-crystalline phenylnaphthalene derivatives. Thus, the dendrimer backbone can avoid crystallizing and exhibit high carrier transportation at room temperature. Moreover, the phenylnaphthalene dendrimers also form a homeotropic structure on the substrate. The homeotropic alignment seems to be better for the construction of vertical type transistor. Less