基于氢键的侧链型超分子电光聚合物的制备与表征

设计并制备了一种基于氢键的侧链型超分子聚乙烯基吡啶电光聚合物,非线性发色团与聚合物主链之间的氢键作用经红外光谱进行表征。采用氢键将发色团挂接到聚合物,可一定程度地抑制发色团分子的聚集,防止宏观相分离,实现发色团的高浓度掺杂。同时,利用超分子氢键作用挂接也可在一定程度上抑制发色团间的偶极-偶极相互作用力,测得此体系极化电光聚合物薄膜的最大电光系数为17.6 pm/V。     

一种光交联电光聚合物的合成及其外部电光测量

合成了一种新的带有光交联基团的电光聚合物,其高分子基体是双酚A环氧树脂,二阶非线性生色团对硝基苯胺和光交联基团肉桂酰氯都键接在高分子链上.将聚合物溶解后旋涂成膜,对薄膜进行电晕极化.极化的后阶段用紫外光照射,使聚合物体系交联成网络结构,形成生色团取向长时间稳定的聚合物电光薄膜.用这种聚合物电光薄膜构成外部电光调制系统,测量了共面波导上的电信号.     

异氰酸酯交联的环氧树脂基二阶非线性光学聚合物

通过双酚A 二 (缩水甘油醚 )与苯胺的逐步聚合反应合成环氧树脂类先驱聚合物BPAN ,进一步通过先驱聚合物的后重氮偶合反应 ,制备了侧链带偶氮生色团的二阶非线性光学聚合物BPAN 1A NT .将BPAN 1A NT与适当量的异氰酸酯交联剂M2 0S混合 ,得到了双组分非线性光学聚合物体系BPAN 1A NT M2 0S .该体系在电场极化的同时可发生交联固化 ,极化后其二阶非线性光学系数高达 10 5 2pm v(λ =1 0 6 4 μm) ,同时还具有很好的极化偶极取向稳定性 ,2 0 0℃时的非线性光学系数仍可维持在初始的 80 %以上 .上述双组分非线性光学聚合物材料 (BPAN 1A NT M2 0S)同时具有高二阶非线性光学系数和高极化偶极取向稳定温度 ,可以预期 ,在聚合物电光调制器、光开关等器件中将有很好的应用前景 .     

PMMA型非线性光学膜的制备及其极化取向

采用封管反应, 以较高产率(80%以上)合成了一种PMMA型的极化非线性光学聚合物材料. 该材料具有很好的成膜性, 用电晕极化的方法使其旋涂膜中的生色团极化取向, 并利用偏振红外光谱和偏振紫外光谱等方法, 对膜中生色团极化前后的取向进行了研究.     

一种新型的交联极化聚合物的合成及性能研究

以成膜性能优异、主链上含有多个羟基的聚双酚A二缩水甘油醚-苯胺(BPAN)为骨架,将二阶非线性光学活性发色团分子以键合形式挂接到聚合物主链上,形成新型侧链型聚合物.此聚合物保留了原聚合物体系成膜性好和可进一步交联等优点.极化过程中以含有异氰酸酯基的同种发色团分子作为交联剂,得到发色团含量进一步提高的交联型极化聚合物.采用衰减全反射法(ATR)测得体系的电光系数(r₃₃)为6.7 pm/V(1315 nm).     

新型含苯并呋喃的非线性光学发色团的合成与性能研究

以基于久洛尼定的苯并呋喃衍生物为电子给体,三氰基呋喃衍生物为电子受体经Knoevenagel缩合反应合成了一种新型含苯并呋喃的非线性光学发色团(JBFC),其结构经¹H NMR, ¹³C NMR和HR-MS表征,并通过紫外可见吸收光谱、热重分析、理论计算和电光性能测试对非线性光学发色团的性能进行了研究。结果表明：JBFC具有较好的热稳定性,T_d值（质量减少5%时）为214 ℃,将JBFC制得的极化电光聚合物薄膜的电光系数为30 pm·V^-1。     

含呋喃共轭桥有机非线性光学生色团的合成及性能研究

通过两次羟醛缩合反应合成了一种含呋喃共轭桥的有机非线性光学生色团分子2-二氰亚甲基-3-氰基-4-[2-(4-二乙氨基-苯乙烯基-呋喃基-5)-乙烯基]-5,5-二甲基-2,5-二氢呋喃(EFFC), 用IR谱、¹H NMR谱以及元素分析表征确认了其结构. 热失重分析表明, 材料的热分解温度T_d为250℃. 用密度泛函理论的B3LYP方法在6-31G基组下对这种生色团分子进行了结构优化, 并在相同基组下对分子的静态二阶极化率进行了计算, 分子的b₀=6.5×10^-28 esu. 将分子以18%的质量比与聚砜进行主-客体掺杂, 用溶胶凝胶法制备成膜后进行极化, 用二次谐波法对掺杂极化聚合物薄膜的电光系数进行测量, 其r₃₃值最高达到80 pm/V.     

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.     

含苯并噻唑氟化聚酰亚胺制备及非线性光学性质

采用Mitsunobu反应将杂环偶氮生色分子键入氟化聚酰亚胺母体制备新型的侧链含氟聚酰亚胺非线性光学(NLO)材料.采用傅里叶变换红外(FT-IR)光谱、紫外-可见(UV-Vis)光谱、1H核磁共振(1HNMR)谱和凝胶色谱(GPC)对材料进行表征.热分析结果表明侧链型聚酰亚胺具有较高的玻璃化转变温度(Tg)(184-188℃),热分解温度(Td)高达322℃.采用简单全反射法于1550nm处测定聚酰亚胺的电光系数(γ33),含苯并噻唑偶氮苯胺的聚酰亚胺(PI1)具有较高的电光系数15pm·V-1.     

二阶非线性光学聚氨酯对电光效应的共振增强

二阶非线性光学聚合物是最有希望实现在电光器件方面应用的材料之一.该类材料的非线性光学系数很高,响应速度快,与半导体材料的相容性较好,且比有机和无机晶体的制备更方便.目前所用的电光调制器多为光传输型,高光学活性的极化聚合物一般光学损耗较大,尤其是其吸收波段更大,使得调制器只能在其透明波段内使用,否则,传输型波导器件由于这种损耗将无法使用.     

含对硝基偶氮苯胺生色团的键合型有机/无机复合材料的合成及其二阶非线性光学特性

以γ 缩水甘油氧丙基三甲氧基硅烷 (KH5 6 0 )作中间体 ,用溶胶 凝胶 (Sol Gel)法合成了含对硝基偶氮苯胺 (DO3)生色团的新型键合型有机 /无机复合非线性光学 (NLO)材料 ,在这种有机生色团与无机玻璃键合形成的交联网络结构中 ,无机玻璃的刚性三维结构和优良的高温稳定性能有效抑制NLO生色团的极化松弛 .二次谐波信号 (SHG)测量表明 ,合成的键合型聚合物膜的二阶非线性光学系数 (d33)值达 5 79× 10 -7esu ,NLO稳定性也较好 ;在室温下放置 90天后 ,其d33 值能维持初始值的 93 5 % ;在 10 0℃下放置 30 0min后 ,其d33 值仍能维持初始值的 6 0 %     

Dual fluorescence of 4-N,N-dimethylaminopyridine. Role of hydrogen-bonded complex in the ground state

A correlation is shown between the appearance of the dual fluorescence of 4-N,N-dimethylaminopyridine (DMAP) solutions and the formation of hydrogen-bonded of complexes in the ground state. A comparative absorption study between pyridine, N,N-dimethylaniline and DMAP shows that the hydrogen-bonded complex is situated on the amino nitrogen of DMAP. A “pretwisted” conformation of DMAP in the ground state isassumed due to this hydrogen-bonded complex. Simulations by intermolecular interaction calculations and spectroscopic calculations (CNDO/s) confrim the “twisting” influence of water molecules (and/or any other hydrogen bonding) on the amine in the ground state. This “pretwisting” in the ground state by hydrogen bonding is common in many other aromatic amines. Moreover, the deforming role of hydrogen bonding in the ground state seems to be a general phenomenon in flexible aromatic molecules.     

Intramolecular hydrogen bonding and calixarene-like structures in p-cresol/formaldehyde resins

The nature of the strong hydrogen bonds found in p-cresol/formaldehyde (PCF) resins, compared to ordinary phenolic compounds, is studied. The evidence from FTIR spectroscopy indicates that this strong interaction is due to intramolecular hydrogen bonding from “calixarene-like” structures. The formation of this structure in PCF is enabled by its “linear” (all-ortho-linkage) structure, which is not present in branched resins. Additionally, a transition is observed at around 175 to 200°C where the intramolecular hydrogen bonded structure is lost. This structure cannot be recovered upon cooling or annealing due to restrictions on conformational rotations that are coupled to a new pattern of intermolecular hydrogen bonding. However, the structure is reformed by dissolving the resin in solution and casting new films.     

Stable second‐order NLO semi‐IPN system based on bipyridine‐containing polyimide and alkoxysilane dye

An organosoluble polyimide based on bipyridyl moiety and an alkoxysilane dye have been developed for second‐order non‐linear optics (NLOs). This bipyridine‐containing polyimide exhibits a glass transition temperature of 254°C and a degradation temperature of 400°C. An NLO‐active semi‐interpenetrating network (IPN) system was prepared by blending the polyimide with the alkoxysilane dye via in situ sol‐gel process of alkoxysilane. The selection of this bipyridine‐containing polyimide as the polymeric matrices provides improved solubility and thermal stability, and most importantly enhanced intermolecular interactions. No aggregation of the NLO chromophores in the polyimide matrices was observed through morphology and NLO studies. Under the limitation of chromophore degradation at elevated temperatures, the pristine poled/cured alkoxysilane dye exhibits poorer long‐term stability. By introducing the polyimide upon a silica network by the semi‐IPN system, randomization of the oriented chromophores can be effectively suppressed. Using in situ contact poling, the r₃₃ coefficients of 2.2–17.0 pm/V were obtained for the optically clear semi‐IPN NLO materials. Excellent temporal stability (100°C) was also achieved for these semi‐IPN materials. Copyright © 2005 John Wiley & Sons, Ltd.     

Hybrid materials covalently incorporated with isophorone-based dyes through sol-gel process for nonlinear optical applications

Two new push-pull type second-order nonlinear optical (NLO) active isophorone-based alkoxysilane dyes with the same acceptor were synthesized and characterized. One silane (ICTES-HEMA) bears a chromophore with a hydroxyethyl methylamino donor and the other silane (ICTES-HMPP) is a bulkier analogue with a hydroxymethyl diphenylamino donor. Transparent, homogeneous films were prepared via the copolymerization of tetraalkoxysilane (TEOS) and different NLO silanes with the ratio of 5:1. The d(33) values obtained for the HEMA and HMPP films are 46.3 and 20.6 pm/V, respectively. Normalized UV-vis spectra reveal that the introduction of a diaryl group would help to prevent unfavorable organization of the chromophores. The reorientation dynamic stabilities of the samples were studied by second-harmonic generation (SHG) measurements, demonstrating that bulkier chromophores incorporated in sol-gel materials would not necessarily lead to higher stabilities over time.     

Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior

A new, highly adaptable type of phosphinamide‐based hydrogen bonding is representatively demonstrated in π‐conjugated phosphole materials. The rotational flexibility of these intermolecular P=O?H?N hydrogen bonds is demonstrated by X‐ray crystallography and variable‐concentration NMR spectroscopy. In addition to crystalline compounds, phosphinamide hydrogen bonding was successfully introduced into the self‐assembly of soft crystals, liquid crystals, and organogels, thus highlighting the high general value of this type of interaction for the formation of organic soft materials.     

Theoretical study of intermolecular spin alignments through hydrogen bonding of the carboxy group

Intermolecular magnetic interactions through hydrogen bonding of the carboxy group for dimers of allyl, benzyl, and chlorinated benzyl radicals have been investigated as model systems by the ab initio molecular orbital (MO) and density functional theory (DFT) calculations. It is found possible to propagate magnetic interaction through hydrogen bonding, although the effect is small. The spin densities of π- and σ-electrons have shown that antiferromagnetic coupling exists between the two intermolecular oxygen atoms in the ground state. This behavior is consistent with McConnell’s model, being applied to the planar configuration of the two hydrogen-bonded carboxy groups.     

Revisiting the electronic excited-state hydrogen bonding dynamics of coumarin chromophore in alcohols: Undoubtedly strengthened not cleaved

In the present work, the electronic excited-state hydrogen bonding dynamics of coumarin chromophore in alcohols is revisited. The time-dependent density functional theory (TDDFT) method has been performed to investigate the intermolecular hydrogen bonding between Coumarin 151 (C151) and methanol (MeOH) solvent in the electronic excited state. Three types of intermolecular hydrogen bonds can be formed in the hydrogen-bonded C151–(MeOH)₃ complex. We have demonstrated again that intermolecular hydrogen bonds between C151 and methanol molecules can be significantly strengthened upon photoexcitation to the electronically excited state of C151 chromophore. Our results are consistent with the intermolecular hydrogen bond strengthening in the electronically excited state of Coumarin 102 in alcoholic solvents, which has been demonstrated for the first time by Zhao et al. At the same time, the electronic excited-state hydrogen bond cleavage mechanism of photoexcited coumarin chromophores in alcohols proposed in some other studies about the hydrogen bonding dynamics is undoubtedly excluded. Hence, we believe that the two contrary dynamic mechanisms for intermolecular hydrogen bonding in electronically excited states of coumarin chromophores in alcohols are clarified here.     

组装合成超分子液晶聚合物动态功能材料

从电荷转移相互作用。离子相互作用及氢键组装三个方面综述了通过分子自组装合成超分子液晶聚合物近年来的最新研究成果。总结 阴谋家类体系作为动态功能材料在器件化及应用方面所取得的重要进展，并展望了这一领域今后的发展方向。     

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores

The ground-state dipole moments and second-order nonlinear optical （NLO） properties of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures have been investigated by using the second-order MФller-Plesset （MP2） and density functional theory （DFT） methods with the basis set of 6-31＋G（d）. According to the calculated results, the relationship between the molecular static first hyperpolarizability （βμ） and the directions of electron transition has been summarized. In terms of the sign of βμ, these 1D organic chromophores were classified into two categories： type Ⅰ with negative βμ and type Ⅱ bearing positive βμ. The analyses show that the remarkable difference of the first hyperpolarizabilities between Ⅰ and Ⅱ chromophores is associated mainly with the electrostatic interaction between terminal groups and the transport electrons in excited states. Moreover, different from the popular viewpoint, the obtained results also show that most of this series of 1D D-B-A molecules are more charge-separated in the ground states than in the excited states. As a whole, this theoretical investigation, to some extent, can be considered as a useful reference in designing the NLO chromophores with large first hyperpolarizabilities.