两种侧链偶氮聚电解质自组装膜中生色团取向研究

用偏振紫外光谱研究了两种侧链偶氮聚电解质静电逐层自组装膜中偶氮生色团的初始取向 .讨论了不同的组装条件对自组装膜中偶氮生色团取向的影响 .进一步探讨了偶氮聚电解质自组装膜的结构特点 .研究表明 ,侧链偶氮聚电解质自组装膜中的偶氮生色团存在一定程度的面内取向 ,自组装的各种影响条件和聚合物结构等 (pH值、侧链柔性间隔基团长度、以及偶氮生色团官能度等 )与自组装膜中偶氮生色团的面内取向程度存在一定的相关性 .通过研究偶氮生色团的取向和影响因素 ,可以深入认识侧链偶氮聚电解质的自组装行为     

端基对侧链型偶氮聚电解质自组装膜内生色团取向的影响

用偏振紫外光谱研究了 4种带有不同端基的侧链型偶氮聚电解质静电逐层自组装膜中偶氮生色团的初始取向 .讨论了不同的端基对偶氮生色团在自组装膜中初始取向的影响 .进一步探讨了偶氮聚电解质自组装膜的结构特点 .研究表明 ,侧链型偶氮聚电解质自组装膜中偶氮生色团普遍存在一定程度的沿面取向 .偶氮生色团所带端基的类型对其在自组装膜中的取向程度有较大的影响 ,这主要取决于偶氮生色团与聚阳离子基底的电荷相互作用和极性相互作用等 .对偶氮生色团在水溶液中能形成H 聚集体的自组装膜来说 ,H 聚集体对生色团取向也有一定的影响 .结果表明 ,在制备需控制生色团取向性的自组装膜时 ,要考虑生色团上的不同端基对取向的影响     

重氮偶合方法合成主链型光响应偶氮聚合物

提出了一种利用重氮偶合方法合成主链偶氮聚合物的新方法,合成了一种主链含有假芪型偶氮生色团的聚合物.对合成聚合物的结构、热性能以及光响应性能进行了详细表征.在线偏振激光的作用下,聚合物膜中的偶氮苯生色团发生光致取向,用偏振紫外-可见光光谱测量了此聚合物膜的二向色性,得到聚合物膜的取向有序度为0.03.用波长为488 nm,能量密度为150 mW/cm2的相干Ar+激光对聚合物膜照射1000 s,得到形貌规整的正弦波形表面起伏光栅,光栅的周期为900 nm,起伏深度为89 nm.     

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     

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.     

光响应性偶氮聚电解质自组装研究

将3种侧链带有不同偶氮生色团的聚电解质,用逐层浸渍的方法使其组装成多层膜.利用原子力显微镜(AFM)研究了自组装膜的表面形貌以及随着组装层数增加的变化.详细研究了在紫外光的照射下,薄膜内偶氮生色团由反式到顺式构型的光响应转变,以及在暗室中由顺式回复到反式构型的回复特性.与自组装膜的光响应性和相应的旋涂膜进行比较发现,其中的PNAPE/PDAC自组装膜没有明显的光色效应,而PEAPE/PDAC,PPAPE/PDAC具有明显的光色效应.在暗室中,随生色团的结构不同和在不同的凝集态中,由顺式回复到反式构型的速率明显不同.     

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 .     

重氮偶合反应合成超支化偶氮聚合物的光响应性能研究

利用重氮偶合反应和后重氮偶合反应制备了主链和端基含有不同假芪型偶氮苯生色团的超支化偶氮聚合物.利用氢核磁共振、紫外光谱、红外光谱等分析手段确定了合成聚合物的结构、玻璃化转变温度和光谱特性等.研究了聚合物光致二向色性的性能,此聚合物的取向有序度为0.063.用两束相干的P偏振Ar+激光对聚合物膜进行光加工,得到形状规则的正弦波形表面起伏光栅,末端偶氮苯基团的引入极大地增加了超支化偶氮聚合物的光响应速度.     

含三氟甲基偶氮生色团环氧树脂类聚合物合成和光致表面自结构研究

利用后重氮偶合反应,将4-(三氟甲基)苯胺的重氮盐与两种具有高苯胺残基密度的环氧树脂类前体聚合物在极性有机溶剂中反应,制备了两种具有高生色团密度的环氧树脂类偶氮聚合物PEP-AZ-CF3和PEP-35AZ-CF3.利用1H-NMR、FTIR、UV-Vis和DSC等分析方法对2种偶氮聚合物结构、热性能及吸收光谱性能进行了分析及表征.研究了在不同波长的激光(488、532及589 nm)照射下,2种偶氮聚合物薄膜光致表面自结构的形成.研究结果表明,入射激光的波长对偶氮聚合物表面自结构现象的形成有明显影响.仅在波长488 nm的偏振激光(线偏振光或圆偏振光)照射下,2种偶氮聚合物薄膜表面能观察到自结构现象.圆偏光比线偏光更有利于诱导表面起伏结构的形成,但形成的表面结构不具备长程取向有序性.聚合物生色团中偶氮键邻位的取代甲基对表面自结构的形成起到阻碍作用.     

浸泡法和旋涂法对偶氮聚电解质静电吸附自组装膜结构及性能的影响

利用浸泡和旋涂静电吸附自组装技术制备了含有偶氮生色团的聚电解质薄膜,比较了两种方法在自组装膜生长机理、膜结构以及膜光学性能方面的差异.利用紫外光谱和椭偏仪检测自组装膜的生长情况,利用原子力显微镜对膜表面结构进行了表征,并用偏振激光在膜表面进行了写光栅实验.结果表明,采用浸泡法和旋涂法都可以制备出表面光滑均匀的含偶氮生色团的聚电解质自组装膜.但是浸泡法自组装膜的生长速度要比旋涂法快.在自组装膜厚度较小的情况下,旋涂法得到的自组装膜可以写出明显的光栅而浸泡法不可以.随着自组装膜厚度的增加,两种方法得到的自组装膜都可以写出明显的光栅.这些结果说明浸泡法自组装膜内部聚电解质分子的层间穿插比较严重,而旋涂法自组装膜内分子穿插要弱得多.     

新型可溶性偶氮聚酰亚胺及其作为液晶光定向层应用的初步研究

以 4 ,4′ 二 (1,2 苯二酸酐 4 羧酸酯 )偶氮苯为二酐单体 ,4 十六烷氧基 4′ ,4″ 二氨基三苯甲烷为二胺单体 ,通过缩聚反应合成了可溶性偶氮聚酰亚胺 .采用红外光谱、氢核磁共振、紫外光谱和热分析等手段 ,对产物的结构、热性能及光学性能等进行了表征 .在紫外光辐照下 ,上述聚合物表现出明显的光色效应 .经线性偏振紫外光 (LPUV)辐射后的上述偶氮聚酰亚胺定向层能诱导液晶盒中液晶分子发生定向沿面排列 ,且取向均匀 .上述实验表明 ,合成的偶氮聚酰亚胺是一类潜在的液晶光定向材料 .     

Synthesis,characterization and photoinduction of optical anisotropy in liquid crystalline diblock azo‐copolymers

Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline (LC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobenzene content in these copolymers ranges from 52 to 7 wt %. For an azo content down to 20% they exhibit a LC behavior similar to that of the azo homopolymers. Thin films of these copolymers were characterized by transmission electron microscopy (TEM). A lamellar nanostructure was observed for azo content down to 20 wt %, while no structure is observed for the copolymer with a 7% azo content. The optical anisotropy induced in these films by illumination with linearly polarized 488 nm light was studied and the results compared with those of the azo homopolymer and of a random copolymer with a similar composition. The formation of azo aggregates inside the azo blocks is strongly reduced in going from the homopolymer to the copolymers. Photoinduced azo orientation perpendicular to the 488 nm light polarization was found in all the polymers. The orientational order parameter is very similar in the homopolymer and in the block copolymers with an azo content down to 20 wt %, while it is much lower in the random copolymer and in the 7 wt %. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1899–1910, 2007     

主链型聚氨酯光动力高分子的合成与表征

合成了一种主链含推拉电子型偶氮苯基团的聚氨酯光动力高分子 .对聚合物的结构、热性能及光学性能进行了表征 .此聚合物为主链含假芪型偶氮生色团的无定形高分子 .用 4 88nmAr+ 激光对聚合物薄膜进行光加工 ,得到了规则的正弦表面起伏光栅 ,其起伏深度大于 2 0 0nm .光栅的一级衍射效率可达 2 4 % .     

Improvement of LPS-based command surfaces: effect of inserting a flexible disiloxane segment into the azo side chain on photo-driven response

A new synthetic route for azo grafted ladder-like polysilsesquioxanes (LPS) used for fabricating command surfaces has been developed. In comparison with previous work, the grafting ratio of azobenzene on the LPS backbone could be controlled more accurately and the low molar mass impurity, which might influence the concerted action of the azobenzene units as command moieties on the surrounding LC molecules, could be readily removed by repeated precipitation. The results of our measurements indicate that inserting a flexible disiloxane segment into the spacer of the side group can improve the photo-driven response. The response steepness of a LC cell is 20 times that of our previous result. However, the response speed also depends on the spacer length and the content of azo side groups. Using azo grafted LPS with a shorter spacer as the material for the command surface, the response speed is faster than with a longer spacer. Optimum response can be achieved at an azo content of 10 mol %.     

Improvement of LPS-based command surfaces: effect of inserting a flexible disiloxane segment into the azo side chain on photo-driven response

A new synthetic route for azo grafted ladder-like polysilsesquioxanes (LPS) used for fabricating command surfaces has been developed. In comparison with previous work, the grafting ratio of azobenzene on the LPS backbone could be controlled more accurately and the low molar mass impurity, which might influence the concerted action of the azobenzene units as command moieties on the surrounding LC molecules, could be readily removed by repeated precipitation. The results of our measurements indicate that inserting a flexible disiloxane segment into the spacer of the side group can improve the photo-driven response. The response steepness of a LC cell is 20 times that of our previous result. However, the response speed also depends on the spacer length and the content of azo side groups. Using azo grafted LPS with a shorter spacer as the material for the command surface, the response speed is faster than with a longer spacer. Optimum response can be achieved at an azo content of 10 mol %.     

Silicon‐containing azo polymers with paired mesogens and their applications to optical memory media

We synthesized a novel photoresponsive monomer, silicon‐containing azo monomer with paired mesogens in the side chain, by reacting 3‐methacryloxypropylmethyldichlorosilane with 2‐[2‐(4‐cyano‐azobenzene‐4′‐oxy)ethylene‐oxy]ethyl alcohol, a mesogenic group. Corresponding homopolymer and copolymers with methyl methacrylate were generated via radical polymerization with AIBN as a radical initiator. Investigations of their thermal properties and optical textures confirmed the monomer and the homopolymer have smectic structures. Homo‐ and copolymer films showed high potential as reversible data recording media via photoinduced alignment of azobenzene groups with irradiation of a linearly or circularly polarized light. Out of all the samples, the copolymer films with high azo dye contents showed the best resolution in the recorded data as well as the fastest response to a pump beam due to large optical birefringence induced in a write‐in process. Strong dependence of the stability of the data stored in the films on the glass transition temperature of the polymers was also observed. In addition, high‐quality holographic grating patterns were inscribed even on the copolymer film with azo molar content of only 7.0% using a modified two‐wave mixing technique. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6734–6745, 2008     

一种具有可逆光加工特性的偶氮聚电解质的合成与表征

合成一种具有可逆光加工特性的偶氮聚电解质(PAA-AZ),用核磁、热分析、紫外-可见光谱、接触角及GPC等手段对其进行了结构和性能表征.PAA-AZ的旋涂膜用线偏振Ar+激光照射一段时间,在原子力显微镜(AFM)下观测其表面,膜表面形成了规整有序纳米尺寸的三维表面图案表面起伏光栅(起伏深度为100nm).用氦氖激光检测了PAA-AZ旋涂膜一级衍射效率与光照时间的关系.