Study on Synthesis of Tailor-Made Block Copolymers Having Side Chains of Liquid Crystal and its Application to Recording Materials.

要获得分子存储，不仅需要在记录时染料容易异构化到亚稳态，保持对热反向异构化的抑制，在删除时容易反向异构化，而且还需要高机械强度。为此，希望将双功能管芯用作具有高玻璃化转变温度组分的嵌段共聚物的交联剂。发现N，N-二甲基-4-乙烯基苯乙胺(PTA)是一种适合目前用途的单体。PTA单体的制备和纯化并不是很困难。以异丙基钾或异丙基铯为引发剂，可在195K的四氢呋喃中进行阴离子聚合。所得聚对苯二甲酸乙二醇酯的分子量分布较窄。如果PTA先于苯乙烯聚合，则可以得到一种定义良好的两嵌段共聚物，即聚(PTA-b-苯乙烯)。聚(PTA)的玻璃化转变温度为315K。嵌段共聚物与对，p‘-二(氯甲基)偶氮苯(CAB)的季胺化可以很容易地以膜的形式进行。通过紫外光照射可以使这种结合的CAB从反式异构化为顺式。热反向异构化在室温下可以忽略不计，但在高于聚对苯二甲酸乙二醇酯玻璃化转变温度时容易发生热反向异构化。这些事实使我们可以通过使用聚(PTA)和CAB来制作分子记忆。

To obtain a molecular memory, one needs not only the conditions, easy isomerization of dye to metastable state in recording, suppression of thermal backward isomerization in keeping, and easy backward isomerization in deleting, but also high mechanical strength. For the purpose, it is desirable to use bifunctional die as cross-linker onto block copolymer having a component of high glass transition temperature. It was found that N, N-dimethyl-4-vinylphenethylamine (PTA) is an appropriate monomer for the present purpose. Preparation and purification of PTA monomer is not so difficult. PTA can be polymerized anionically in THF at 195K with cumyl potassium or cumyl cesium as an initiator. The obtained poly (PTA) has a narrow molecular weight distribution. A well defined diblock copolymer, poly (PTA-b-styrene) can be obtained, if PTA is polymerized prior to styrene. The glass transition temperature of poly (PTA) is 315K. A quarternization of the block copolymer with p, p'-bis (chloromethyl) azo-benzene (CAB) can be easily carried out in a membrane form. An isomerization of such incorporated CAB from trans to cis form can be made by irradiation of UV light. Thermal backward isomerization is negligible at room temperature but easy at a temperature higher than the glass transition temperature of poly (PTA). These facts allow us to make a molecular memory by the use of poly (PTA) and CAB.