新型支化侧链偶氮聚电解质的合成与性能研究

通过后重氮偶合的方法合成了一种含支化侧链偶氮苯生色团的聚电解质 (PBANT AC) .用IR、NMR、DSC、UV和元素分析等手段对聚合物的结构和性能进行了表征 .研究发现 ,在不同比例的水和四氢呋喃混合溶剂中PBANT AC的紫外 可见光光谱有很大的差别 .这种差别反映了PBANT AC分子中的偶氮苯生色团的不同聚集状态 .通过静电吸附逐层自组装的方法将PBANT AC分子组装成多层膜 .在 488nm的偏振Ar+ 激光的照射下 ,聚合物薄膜中的偶氮苯生色团可发生光致取向 ,取向有序度约 0 0 5 .偶氮苯生色团的顺反异构化反应使H 聚集体在光照后发生解聚集     

过渡金属偶氮苯衍生物二阶非线性光学性质的密度泛函理论研究

采用含时密度泛函理论方法(TDDFT)计算了IB族过渡金属及第5周期的金属杂化偶氮苯生色团的二阶非线性光学极化率。研究了金属杂化偶氮苯生色团的电子激发跃迁。结果表明, 与金属离子络合后的杂化偶氮苯生色团, 二阶非线性光学极化率明显改变, 是金属的推拉电子效应的结果。IB族金属的在原有机偶氮苯共轭体系的电荷转移方向的强拉电子效应, 增大了电荷转移范围, 使二阶非线性光学极化率增大。与Nb络合的杂化生色团, 沿原电荷转移相反的方向拉动电荷, 电荷转移跃迁局限于金属离子附近, 未能产生大的激发跃迁偶极矩, 体系的二阶非线性光学响应因而降低。激发跃迁能量是另一个主要影响因素, 同一类跃迁中, 金属杂化生色团的跃迁能量越低, 其二阶非线性光学响应就越大。络合Rh的生色团与Nb杂化生色团类似, 电荷转移跃迁范围都比较小, 同时由于Rh与羧基结合时几乎垂直羧基平面, 电荷同时沿X, Y方向转移跃迁, 属于二维电荷转移类型。     

表面起伏光栅形成速率的影响规律 Ⅰ.偶氮生色团种类和官能度的影响

设计并合成了含有不同生色团以及不同官能度的环氧树脂基偶氮高分子 ,系统研究了偶氮生色团的种类和官能度对光栅形成速率的影响规律 .实验结果表明 ,偶氮苯对位是羧基的聚合物的光栅形成速率明显快于偶氮苯对位是硝基的聚合物 ,光栅形成速率随偶氮生色团官能度的增加而加快 .这两类聚合物都可以形成规整的可擦式表面起伏光栅     

含偶氮苯非线性光学生色团末端烯的合成

采用酰氯酯化法,通过对烯丙氧基苯甲酰氯与胺基偶氮苯反应,合成了6个含偶氮苯非线性光学生色团的末端烯,其结构经1H NMR, IR和元素分析表征.     

后重氮偶合法制备含硝基偶氮苯咔唑类聚合物

后重氮偶合;咔唑;生色团;后重氮偶合法制备含硝基偶氮苯咔唑类聚合物     

两种偶氮分子玻璃材料的光致取向特性

利用光诱导双折射和偏振红外光谱法研究了2种无定形树枝状偶氮分子材料G1-AZ-CN和G2-AZ-CN的光致取向行为, 对其偶氮生色团及非光响应性星形核的光致取向速度、 取向松弛速度和饱和取向程度进行了系统研究. 结果表明, G2-AZ-CN中偶氮生色团和星形核的光致取向速度快于G1-AZ-CN, 但其取向松弛速度慢于G1-AZ-CN, 这与G2-AZ-CN具有更高的偶氮生色团密度有关. G1-AZ-CN具有较高的饱和取向程度及较好的取向稳定性. 与具有相同类型偶氮生色团的偶氮聚合物BP-AZ-CN相比, G1-AZ-CN和G2-AZ-CN中偶氮生色团表现出较慢的取向速度. 其取向行为与其特殊的星形分子结构有关.     

偶氮苯侧链结构对聚丙烯酸酯三阶非线性光学性能影响

设计合成了一系列含偶氮苯非线性生色团的丙烯酸酯,并采用溶液聚合法合成了功能化的聚丙烯酸酯,利用FTIR、NMR、UV等对化合物的结构进行了表征,证实得到了指定结构的化合物.利用Z扫描技术对合成的聚丙烯酸酯的非线性光学性能进行了研究,通过对聚合物的非线性光学吸收拟合,计算得到非线性吸收系数β和三阶非线性系数χ(3),并探讨了取代基生色团分子结构与高分子三阶非线性光学性能的关系,结果显示增大侧链生色团π电子离域长度或强DπA(推拉基团)结构均可有效提高聚合物的三阶非线性光学性能.     

含偶氮咔唑生色团氧化乙烯功能单体的合成及其聚合反应研究

设计并合成了含偶氮苯生色团的环氧类功能单体和仅含咔唑环的单体,并以一定比例通过阳离子开环聚合合成了三个新的非共轭主链具有光折变生色团的聚合物,并用GPC、DSC、FT-IR、TG和UV-Vis等手段对所得聚合物进行了表征,考察了共聚单体配比对聚合物玻璃化转变温度的影响。UV-Vis谱图说明聚合物的最大吸收波长取决于生色团的种类。DSC结果显示,通过改变两个单体的配比可以有效调节共聚产物的玻璃化转变温度。TG结果显示,聚合物具有好的热稳定性,325℃左右开始分解。     

新型有机/无机聚合物网络的合成与二阶非线性光学

合成了含双官能团的生色团4’-(N,N-二羟乙基)氨基-4-硝基偶氮苯(DR19),采用溶胶-凝胶方法,通过"两端"交联设计合成了光学性能良好的二阶非线性新型有机/无机复合聚合物网络.经过极化交联后,其在室温和较高温度下均具有良好的二次谐波产生(SHG)稳定性,表明该交联聚合体系能形成致密的硅-氧网络,从而有效地抑制生色团分子的取向松弛.     

支化侧链偶氮聚电解质的光致二向色性和表面起伏光栅

通过后重氮偶合的方法合成了两种含支化侧链偶氮苯生色团的聚电解质PBANT AC和PBACT AC .用红外光谱、氢核磁共振谱、紫外 可见光光谱、热分析和元素分析等手段对聚合物的结构和性能进行了表征 .在 4 88nm的偏振Ar+ 激光的照射下 ,聚合物薄膜中的偶氮苯生色团可发生光致取向 ,取向有序度分别为 0 12和 0 0 9.在干涉偏振激光束的照射下 ,两种聚合物旋涂膜表面均形成了规则的正弦表面起伏光栅 ,其起伏深度分别为 4 0nm和 80nm左右 .用氦氖激光实时检测 ,测定了两种旋涂膜表面起伏光栅的一级衍射效率随光照时间的变化关系 .     

石墨烯/偶氮杂化材料研究进展

石墨烯作为一种新型二维平面纳米材料,表现出许多优异的物理性质.含偶氮苯的化合物和聚合物作为功能材料具有独特的光响应性质.将石墨烯的特性与偶氮材料的光响应性相结合,有望发展一类具有卓越性能的新型光电功能材料.本文总结了石墨烯/偶氮杂化材料这一研究方向的最新进展,重点介绍了杂化材料的制备、表征和光电功能性质等,并简要展望了这类材料的发展前景.     

Crystallization‐Induced Emission of Azobenzene Derivatives

Most azobenzene derivatives are utilized as well‐defined photoresponsive materials, but their emission properties have not been of great interest as they are relatively poor. Here, we report crystallization‐induced emission (CIE) based on the suppression of the photoisomerization of azobenzene derivatives. Although these molecules show negligible emission in solution, their microcrystals exhibit intense emission from the azobenzene moieties as a result of CIE. Upon rapid precipitation, fine particles with low crystallinity were kinetically formed and underwent CIE over time with a concomitant increase in crystallinity. Furthermore, we demonstrated “photocutting” of an emissive single crystal using a strong laser by a combination of CIE behavior and photomelting based on the photoisomerization of the azobenzene moiety. Our results regarding the CIE behavior of azobenzene derivatives in addition to their photoisomerization can provide a new platform for developing photoresponsive luminescent materials.     

偶氮苯高分子的光致可逆固液转变

偶氮苯化合物是一种极具吸引力以及较为常用的光响应材料,本文主要介绍偶氮苯的光响应性质以及一些偶氮苯高分子的合成方法,解析光化学反应导致偶氮苯高分子固液转变的机理,并介绍其在粘结性材料、光致动器、光致热导开关器件及非热纳米压印中的应用。     

Synthesis of a Photoresponsive Liquid‐Crystalline Polymer Containing Azobenzene

The synthesis of an oriented liquid‐crystalline photoresponsive polymer, prepared by polymerization of mono‐ and di‐acrylates, both of which contain azobenzene chromophores, is reported. The prepared free‐standing polymer film shows strong reversible photoinduced deformation upon exposure to unpolarized UV light at 366 nm, as a result of an optically induced isomeric change of the azobenzene moieties in the polymer network. The synthesis process is relatively simple and more efficient compared to conventional ones, and can be used to synthesize other liquid‐crystalline photoresponsive polymers. The use of this photoresponsive polymer film as an optical high‐pass/low‐pass switch under UV or natural light irradiation for a laser beam is demonstrated. This photoresponsive polymer may have applications in robotic systems, artificial muscles, and actuators in microelectromechanical systems (MEMS) and labs on chips.

     

Review of the recent progress in photoresponsive molecularly imprinted polymers containing azobenzene chromophores

Photoresponsive molecularly imprinted polymers (PMIPs) containing azobenzene have received wide research attention in recent years and made notable achievements. This article reviews the recent developments on PMIPs containing azobenzene. Topics include the following: (i) brief introduction of azobenzene, molecularly imprinted polymers, and PMIPs containing azobenzene; (ii) progress in functional monomers, cross-linkers, and polymerization conditions; (iii) preparation methods, properties, applications, as well as advantages and disadvantages of conventional PMIPs; (iv) substrate, preparation method, and applications of photoresponsive surface molecularly imprinted polymers; and (v) some perspectives for further development of PMIPs containing azobenzene.     

Photocontrollable self-assembly

The incorporation of photoswitching molecules into molecular building blocks creates the possibility of photoresponsive self-assemblies in which the self-assembled architecture or self-assembling process can be controlled by external light stimulus. Among the photoswitching molecules, azobenzene has been used most widely by virtue of the large photoinduced changes in its molecular geometry and physical properties. This article reviews how azobenzene can be effectively used to construct the self-assemblies in which supramolecular structure and formation/dissociation can be altered by light.     

Doubly photoresponsive and water‐soluble block copolymers: Synthesis and thermosensitivity

We report the synthesis and investigation of a new type of photoresponsive block copolymers (BCPs). They were designed to comprise two water‐soluble polymers containing two different photoisomerizable moieties (either azobenzene and spiropyran or two different azobenzenes), with the two constituting blocks that, when separated, exhibit a lower critical solution temperature (LCST) in water and can shift their LCST in opposite directions upon photoisomerization (decrease of LCST for one polymer and increase for the other). A variety of such doubly photoresponsive BCPs were synthesized using either azobenzene‐ or spiropyran‐containing poly(N,N‐dimethylacrylamide) (PDMA), poly(N‐isopropylacrylamide) (PNIPAM) and poly[methoxydi(ethylene glycol) methacrylate] (PDEGMMA). Their thermal phase transition behaviors in aqueous solution before and after simultaneous photoreactions on the two blocks were investigated in comparison with their constituting blocks, by means of solution transmittance (turbidity) and variable‐temperature ¹H NMR measurements. The results show that BCPs displayed a single LCST whose shift upon two photoisomerizations appeared to be determined by the competing and opposing photoinduced effects on the two blocks. Moreover, optically controlling the relative photoisomerization degrees of trans azobenzene‐to‐cis azobenzene and spiropyran‐to‐merocyanine could be used to tune the LCST of BCP solution. This study demonstrates the potential of exploring a more complex photoreaction scheme to optically control the solution properties of water‐soluble thermosensitive BCPs. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4055–4066, 2010     

Photoresponsive oil sorbers

A photoresponsive oil sorber (POS) with a hydrophobic, photoresponsive core and shell has been synthesized via suspension polymerization. Lauryl acrylate, isodecyl acrylate, and tert‐butylstyrene were used as monomers, 4‐(methacrylamino)azobenzene (Azo‐M) used as photoresponsive monomer, and bis(methacryloylamino)azobenzene (Azo‐CL‐M) used as photoresponsive surface crosslinker. The POS prefers nonpolar solvents. It absorbed 15 times its dry weight in toluene, 19 times its dry weight in chloroform, and 16 times its dry weight in dichloromethane. Rapid and photoresponsive desorption of solvent (86% of solvent expulsed in 30 min) was characteristic. POS is an excellent gasoline absorber rapidly increasing its body weight in its presence. The new POS is less dense than water, and can potentially be used for cleaning oil spills on water. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 55–62, 2010     

Photoisomerization-induced stable liquid crystalline cubic blue phase

We have succeeded in obtaining a photoinduced liquid crystalline cubic BP in a mixture of photoinactive and photoresponsive bent-core mesogens. The UV stimulus can convert N* to cubic BP through photoisomerization of the azobenzene linkages included in the photoresponsive bent-core molecule.     

Photoresponsive multilayer spiral nanotubes: intercalation of polyfluorinated cationic azobenzene surfactant into potassium niobate

The first successful synthesis of photoresponsive multilayer spiral nanotubes by the introduction of polyfluorinate cationic azobenzene derivative, trans-[2-(2,2,3,3,4,4,4-heptafluorobutylamino)ethyl]-{2-[4-(4-hexyphenylazo)-phenoxy]ethyl}dimethylammonium (abbreviated as C3F7-Azo+), into layered niobate interlayer I by a two-step guest-guest exchange method using the intercalation compound, methyl viologen (MV2+)-K4Nb6O17, as precursor is reported.