基于偶氮吡啶衍生物的超分子功能材料的研究

发布时间：2018-01-06 11:30

本文关键词：基于偶氮吡啶衍生物的超分子功能材料的研究　出处：《北京科技大学》2015年博士论文　论文类型：学位论文

【摘要】：近年来,发展新材料和新器件的重要手段之一就是通过分子的功能化自组装形成规整有序的超分子结构。偶氮吡啶衍生物一方面含有光活性的偶氮基团,分子中的-N=N-双键可以在光和热的作用下进行异构体的转变,同时又含有能够形成氢键、卤键等自组装的吡啶基团,为我们设计材料提供了无限的可能。此外,当紫外光达到一定强度时,还表现出光热效应。因此,受到科学工作者的广泛关注。虽然偶氮吡啶衍生物有着显著的优点,然而目前对于偶氮吡啶衍生物的研究仅限于光响应性液晶和超分子纤维两个领域。本论文着眼于偶氮吡啶衍生物这类材料,结合偶氮吡啶衍生物的光活性和自组装两者的特点,用以开发和探索偶氮吡啶衍生物新的功能和应用,其研究内容如下： (1)首次研究了偶氮吡啶衍生物的光热效应,发现偶氮吡啶衍生物相比于具有类似分子结构的偶氮苯衍生物具有较高的光热转换效率,同时研究了样品单位面积的质量和紫外光的强度对光热转换效率的影响。在此基础上,我们提出了基于偶氮吡啶衍生物光热效应方面的两个潜在应用,其一是应用于光控智能胶黏剂,它在两个玻璃基板之间的剪切强度达到0.661MPa。其二是制备了具有光响应性的聚合物复合双层膜,在紫外光照之下,由于光热能量转换引起的体积变化使其出现光致弯曲的现象,从而有望在光机械领域有所应用。 (2)设计合成了一系列具有不同末端烷基链长度的偶氮吡啶衍生物,将其与卤素分子反应,首次制备出具有较高稳定性的超分子溴键液晶,证明了本体系中的N…Br相互作用足以组装成有序介晶相,同时制备了具有可逆光致相转变行为的碘键液晶。此外,研究了末端烷基链对液晶行为的影响,末端取代基较短时不利于形成液晶相,随着末端烷基链长度的增加,碘键化合物由近晶相液晶转变为向列相液晶,而本体系中的溴键化合物均为近晶相液晶。 (3)利用偶氮吡啶衍生物的自组装特性,研究了多种无机酸和有机溶剂对偶氮吡啶衍生物超分子自组装行为的影响,发现其在不同的环境下具有不同的形貌,并且揭示了酸度离解常数(pKa)对自组装纤维的形成有重要的影响。研究表明,有机溶剂也影响着纤维形成的过程,其中,在丙酮溶剂中的自组装纤维材料能够凝胶化,同时考察了末端烷基取代基对偶氮吡啶衍生物形成凝胶能力的影响,当偶氮吡啶衍生物的浓度增加为60mg/mL时,末端烷基取代基大于12的偶氮毗啶衍生物均可以使丙酮溶剂凝胶化,并且随着末端烷基取代基增加,凝胶化能力增强,同时,偶氮吡啶衍生物作为凝胶因子的浓度越高,越容易形成凝胶。此外,结合TEM和XRD等测试手段,我们提出了超分子纤维的形成机理,即肉眼可见的微米纤维是由纳米级别的纤维组成的。
[Abstract]:In recent years, one of the important means for the development of new materials and devices is through functional molecular and supramolecular structure ordered. Azo azo pyridine derivatives containing a photoactive, molecule of -N=N- can be transformed into double bond isomers in light and heat effect, but also can contain the formation of hydrogen bonds, such as halogen bond self-assembly of pyridine group, we design material provides unlimited possibilities. In addition, when the light reaches a certain intensity, but also show the photothermal effect. Therefore, attention of scientific workers.
Although azo pyridine derivatives have significant advantages, however, for the study of azo pyridine derivatives are only limited to the two areas of the liquid crystal light response and supramolecular fibers. This paper focuses on azo pyridine derivatives of this kind of material, combined with azo pyridine derivatives of optically active and self-assembly of the characteristics of both in function and application development and exploration azo pyridine derivatives, its research contents are as follows:
(1) for the first time on the thermal effect of azo pyridine derivatives, discovered azo pyridine derivatives with azobenzene derivatives compared to photothermal similar molecular structure has high conversion efficiency, and on the unit area of the sample quality and intensity of ultraviolet light on the photothermal conversion efficiency. On this basis, we propose two potential applications azo pyridine derivatives based on the photothermal effect, one is applied to intelligent light controlled adhesive, it between the two glass substrate shear strength reached 0.661MPa. the second is prepared with light responsive polymer composite bilayer membrane, under UV light, volume changes due to heat energy conversion caused by the emergence of light induced the bending phenomenon, which is expected to be used in optical mechanical field.
(2) with a series of different length of the terminal alkyl chain azo pyridine derivatives were designed and synthesized, and the halogen molecular reaction, prepared for the first time the supramolecular bromine bonds with high stability crystal, proved that the system of N... The interaction of Br to assemble into ordered mesophase, while preparing a light induced phase transition behavior of liquid crystal iodine bond. In addition, effects of the terminal alkyl chain on the liquid crystal behavior of the terminal substituent is short is not conducive to the formation of liquid crystal phase, with the increase of the length of the terminal alkyl chain transformation of iodine compounds the smectic liquid crystal nematic liquid crystal, and bromine bond compounds in this system were smectic liquid crystals.
(3) the self-assembly properties of azo pyridine derivatives, studied a variety of inorganic acids and organic solvent effect on azo pyridine derivatives supramolecular self-assembly behavior, found with different morphologies under different environment, and reveals the acidity dissociation constant (pKa) has an important influence on the formation of self-assembled fibers. Show that the organic solvent also affects the process of fiber formation, self-assembly fiber material to gelation in acetone, and investigate the influence of alkyl substituents at the end of gel forming ability of azo pyridine derivatives and azo pyridine derivatives increased when the concentration is 60mg/mL, the end of alkyl pyridine derivatives than azo 12 both can make the acetone gel, and with the end of alkyl substituents increased, the gelation ability, at the same time, azo pyridine derivatives as gelator concentration The higher the degree, the easier the formation of gel. In addition, the combination of TEM and XRD test methods, we proposed the formation mechanism of supramolecular fibers, the visible micron fiber is composed of nanoscale fibers.

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O626.32;TB34

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