Langmuir-Blodgett films of polymethacrylates with side chains containing functionalized aromatic schiff's bases

Langmuir-Blodgett (LB) film formation has been investigated for polymers in which non-linear optical (NLO) moieties are attached to the side chain of a polymethacrylate (PMA) backbone. Polymer monolayers were successfully transferred onto hydrophilic glass substrates using a moving-wall type LB trough. The LB films were characterized by pressure-area isotherms, polarized ultraviolet visible spectra, ellipsometry, and second harmonic generation measurements. The characterization shows that NLO moieties in the side chain are inclined at a shallow angle to the plane of the substrate. The second-order nonlinear optical coefficient and molecular hyperpolarizability were also calculated. © 1993 John Wiley & Sons, Inc.     

Magneto-chiral Nonlinear Optical Effect with Large Anisotropic Response in Two-Dimensional Halide Perovskite

The chiral organic–inorganic halide perovskites (OIHPs) are vital candidates for superior nonlinear optical (NLO) effects associated with circularly polarized (CP) light. NLO in chiral materials often couples with magnetic dipole (MD) transition, as well as the conventional electric dipole (ED) transition. However, the importance of MD transition in NLO process of chiral OIHPs has not yet been well recognized. Here, the circular polarized probe analysis of second harmonic generation circular dichroism (SHG-CD) provides the direct evidence that the contribution of MD leads to a large anisotropic response to CP lights in chiral OIHPs, (R-/S-MBACl)₂PbI₄. The thin films exhibit great sensitivity to CP lights over a wide wavelength range, and the g-value reaches up to 1.57 at the wavelength where the contribution of MD is maximized. Furthermore, it is also effective as CP light generator, outputting CP-SHG with maximum g-factor of 1.76 upon the stimulation of linearly polarized light. This study deepens the understanding of relation between chirality and magneto-optical effect, and such an efficient discrimination and generation of CP light signal is highly applicable for chirality-based sensor and optical communication devices.     

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 .     

PREPARATION AND SECOND-ORDER OPTICAL NONLINEARITY OF NOVEL PHENOXYSILICON NETWORKS BY SOL-GEL PROCESS**

 Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H₂O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d₃₃) of 10-?～10-8 esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120℃) indicated that these films exhibit high d33 stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks.     

In situ poling and orientation stability of chromophore-bearing ladderlike polysiloxanes

A new, specially designed nonlinear optical (NLO) polymer is composed of ladderlike polysilsesquioxane as a backbone and “side-on or end-on” fixed stilbene chromophores. In-situ poling was carried out simultaneously during film formation via solvent evaporation and crosslinking which was caused by sequential hydrolysis and condensation of remained Si-H groups on macromolecules. The dipolar orientation after poling is described by an order parameter Φ which was measured using an original linear optical technique–UV dichroism. Orientation order and its decay are influenced by chromophore loading, crosslinking degree and poling condition. Compared with corresponding single chain polymers, a poled thin film of ladderlike NLO polymers demonstrates more stable poling-induced orientation.     

新型非线性光学杂化材料结构与性能的研究

由硅烷染料ASD与钛酸四正丁酯在酸性条件下共水解、缩合得到杂化材料,利用透射电镜(TEM)和X射线能量色散谱仪(EDS)进行分析,结果表明,杂化溶胶粒子是由硅和钛的化合物组成的球形纳米粒子.由一维刚性取向气体模型计算杂化材料膜再极化后的二阶非线性光学系数χ⁽²⁾为1.43×10^-7esu.差示扫描量热法(DSC)测得杂化材料的玻璃化温度可达469K;用紫外-可见光谱对杂化膜在极化前后的取向及取向稳定性进行了研究.用原子力显微镜(AFM)和X射线衍射(XRD)研究了材料在极化过程中的结晶行为和微观结构对生色团取向稳定性的影响,初次在这种极化后的膜中观察到了介观结构.     

非线性光学活性的侧链型聚丙二酸酯液晶的合成和性质

通过熔融缩聚法合成了含非线性光学活性硝基偶氮苯液晶基元的聚丙二酸酯侧链液晶聚合物 ,采用FTIR、NMR对其结构进行了表征 ,DSC确定其液晶转变温度 ,并用变温WAXD及偏光显微镜 (POM )研究其液晶性质 ,该聚合物为近晶型液晶聚合物 ,POM观察到典型焦锥织构 ,近晶相WAXD有对应层间距为2 74nm和 1 35nm的两个衍射峰 .聚合物旋涂膜经电晕极化 ,紫外光谱测试求得其取向序参数 =0 33 .     

Spectroscopic consideration of the surface potential built across phthalocyanine thin films on a metal electrode

The nonlinear optical properties of tert-butyl phthalocyanine copper Langmuir-Blodgett (CuttbPc LB) films and vacuum-evaporated phthalocyanine copper (CuPc) films deposited on a metal surface were investigated by second-harmonic generation (SHG) spectroscopy. At the organic/metal interface, a space charge field is formed due to the presence of excess charge injected from a metal electrode to the organic layer. Since the Pc molecule has D4h symmetry, an inversion center is present and the optical SH process is not allowed under the electric-dipole approximation. However, the space charge field at the interface directly influences the symmetric structure of the electrons in the Pc molecule. We investigated the contributions of the surface potential to the SHG using Pc LB and vacuum-evaporated films deposited on aluminum (Al) and gold (Au) metal electrodes, where a distinctive difference in the spectrum for the Pc films on the Al and Au surfaces was observed. The contribution of the surface potential was revealed based on the resonant conditions of the SH process, taking into account the electric-quadrupole transition and dc-field-induced electric-dipole transition.     

Synthesis and characterization of interpenetrating polymer networks with nonlinear optical properties

We report the synthesis and characterization of interpenetrating polymer networks (IPNs) exhibiting nonlinear optical (NLO) properties. The network consists of aliphatic polycarbonate urethane (PCU) and poly(methyl methacrylate-co-N,N-disubstituted urea), with a nonlinear optical (NLO) chromophore incorporated into N,N-disubstituted urea. The full IPNs have only one T_g, as determined by differential scanning calorimetry (DSC), together with scanning electron microscopy (SEM) observations, suggest a single phase morphology. The thin films of IPNs are transparent and the unpoled samples produced second harmonic generation (SHG) signals at room temperature. This result indicates that the NLO chromophore is oriented noncentrosymmetrically during the IPN formation process and is tightly held between the permanent entanglements of the two component networks of the IPN. © 1996 John Wiley & Sons, Inc.     

Synthesis and Non-linear Optical（NLO） Properties of a Series of Alkoxysilane Derivative Chromophores

1 Introduction Nonlinear optical materials(NLO) have drawn a great intrest of some scholars and scientists in the last dacades because of their tremendous     

Ultra-thin films of conjugated polymers for opto-electronic applications

Ultra-thin films of precursor polymers for poly(benzimidazole) (PBI), poly(benzoxazole) (PBO), or poly(benzthiazole) (PBT) were formed at air/water interface by spreading monomers and then polymerizing on the water surface. These thin films could be deposited onto appropriate substrates such as quartz by using the Langmuir-Blodgett (LB) method of horizontal lifting. Moreover, the heat treatment of the built-up films of the precursor polymers transformed the films into corresponding PBI, PBO, or PBT, which were high-temperature polymers. The resulting films had uniform and controllable thickness. Electronic and opto-electronic properties of these thin films were evaluated in terms of electric conductivities and nonlinear optical properties.     

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 %     

Organic vapor sensing properties of copolymer Langmuir-Blodgett thin film sensors

In this study, a novel poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] copolymer material is used to fabricate Langmuir-Blodgett (LB) thin films and investigate organic vapor sensing properties. Quartz Crystal Microbalance (QCM) system is used to investigate gas sensing performance of copolymer LB films during exposure to Volatile Organic Compounds (VOCs). The poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] LB thin film sensor sensitivities are determined to be between 0.12 and 0.25 Hz ppm^?1. Detection limits of the copolymer LB thin film are found to be between 23 and 49 ppm against organic vapors. The copolymer LB thin films are more sensitive to chloroform than other vapors used in this study. The results demonstrated that the poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] copolymer material is promising as a organic vapor sensing device at room temperature.     

两种高Tg非线性光学聚合物母体及掺杂,极化的研究

利用具有非线性光学活性的对硝基苯胺掺杂高玻璃化转变温度的聚芳醚砜(PES-C)和聚芳醚酮(PEK-C),得到了两种掺杂含量较高的掺杂型非线性光学聚合物体系。电晕极化表明较高的取向和较慢的松驰。     

Synthesis and Study of Second-order Nonlinear Optical Properties of 3-Substituted-6- (substituted-phenylazo) coumarins

It has attracted a lot of attentions to synthesize and investigate the behaviors of organic second-order nonlinear optical (NLO) materials. [1,2] We have ever reported that acridine derivatives ,[3] 4-substituted-benzylideneoxazol-5(4H)-one[4] and 4,4′-di-styryl-biphenyl derivatives[5] possess good second-order NLO properties. Coumarin derivatives are good organic optical materials and azobenzene derivatives possess a higher second-order nonlinear polarization values, however, there are few reports about the study on the synthetic method, optical behavior, especially,second-order NLO properties of 3-substitued-6-(substituted-phenylazo) coumarin derivatives. Therefore, a series of the following compounds were prepared in order to investigate their NLO behavior.     

Correlation of Molecular Assembly and Interactions in Crystals and Langmuir–Blodgett Films of N‐(2,4‐dinitrophenyl)‐n‐octadecylamine

Correlation of molecular organization in crystals and in ultrathin films is of fundamental interest in the design of molecular materials based on thin films. We have chosen as a test case, N‐(2,4‐dinitrophenyl)‐n‐octadecylamine (DNPOA), a potential candidate for the fabrication of Langmuir–Blodgett (LB) films for quadratic nonlinear optical applications. Like several other 4‐nitroaniline derivatives, DNPOA does not form stable monolayers at the air–water interface. This has precluded investigations of their organization in LB films. We have stabilized composite Langmuir films of DNPOA with the phospholipid molecule DSPC and fabricated their LB films. Successful growth of single crystals of DNPOA allowed structure determination and detailed analysis of molecular associations in the solid state. Electronic absorption spectra of DNPOA in solution, in the solid state and in the LB film are investigated. Modeling of the various spectral signatures by semiempirical computations on molecular clusters extracted from the crystal lattice provides insight into the correlation between the molecular organization in crystals and in LB films.     

Organic vapor sensing properties and characterization of α-naphthylmethacrylate LB thin films

Determination of organic vapor sensing properties of α-Naphthylmethacrylate (α-NMA) monomer based Langmuir-Blodgett (LB) thin films was aimed in this study. LB thin film fabrication was performed on quartz glass and quartz crystal substrates in order to investigate the characterization and organic vapor properties of α-NMA materials by using UV-Visible, Atomic Force Microscopy (AFM) and Quartz Crystal Microbalance (QCM) techniques. π-A isotherm graph was taken and a suitable surface pressure value were primarily determined as 13?mN m^?1 for successful α-NMA LB thin film fabrication. Transfer ratio value was found to be ≥ 0.93 for quartz glass and quartz crystal substrates. The typical frequency shift per layer was obtained as 16.93?Hz/layer and the deposited mass onto a quartz crystal was calculated as 271.30?ng/layer (1.02?ng mm^?2). The sensing responses of α-NMA LB films against dichloromethane, chloroform, toluene and m-xylene were measured by QCM system. Dichloromethane created the maximum shift in the resonance frequency than other organic vapors used in this study. Results exhibited that α-NMA LB thin films were potential candidates for organic vapor sensing applications, especially high sensitive detection of dichloromethane at room temperature.     

Discovery of novel dyes with absorption maxima at 1.1 microm

During the process of developing organic molecules that match the wavelengths used in optical communications, we have discovered a new class of dyes, with absorption maxima at 1.1 mum, and clarified their molecular structures. The synthesis of this class of dyes was supposed to involve unexpected intramolecular tandem reactions, and the effect of alkyl substituents on such a synthesis was investigated. As a result, an effective alkyl-substituent structure for realizing a high synthetic yield and good solubility in organic solvents was found. Furthermore, thin films made of such a highly soluble dye were fabricated by solution-coating, and they exhibited a red-shifted absorption band with a maximum at approximately 1.3 mum, indicating the formation of J-like aggregates. The third-order nonlinear optical susceptibility chi(3) of these thin films at 1.3 mum, which is the wavelength used in optical communications, was measured by the Z-scan technique. The magnitude of chi(3) reaches approximately 10-7 esu. These results suggest that the solution-coated thin films of this type of dye are potential materials for optical switching at 1.3 mum and for other nonlinear optical applications.     

含偶氮生色团的“倒浮萍”聚合物LB膜及其可逆光信息存储特性

含偶氮苯功能基团的聚合物在光电子器件研制中具有诱人的应用前景．Wendorff[1]利用偶氮液晶聚合物首次实现可逆的光学信息存储后，利用偶氮苯分子的激光诱导二向色性和双折射效应实现可逆光学信息存储引起人们极大的兴趣．与传统的利用偶氮苯的顺反异构体实现信息存储的方式相比，这种信息存储方式由于偶氯苯分子始终处于热力学稳定的反式构象，因而具有突出的长期稳定性，具有更广阔的应用前景[1,2]．本工作设计合成了以含有给受体的偶氮苯分子为接枝侧链的两亲性聚合物，并研究了其成膜特性与可逆光信息存储特性．1实验部分两亲性聚合物…     

Interpenetrating polymer networks with stable second order nonlinear optical properties

Interpenetrating polymer networks (IPNs) based on polyurethane and polyacrylate-containing 4-(4'-nitrophenylazo) aniline chromophore groups were synthesized and characterized by infrared spectra, gel content and differential scanning calorimetry. Thin, transparent films of the IPNs were prepared by spin-coating, followed by thermal curing and corona poling. The poled IPN film shows very good optical properties and exhibits only one glass transition temperature. The second-order nonlinear optical (NLO) properties of the poled film were studied by visible light absorbance measurement according to one-dimensional rigid oriented gas model. The second-order nonlinear optical polarizability can reach 10^-7 e.s.u. The poled IPN film of defined composition showed a good temporal stability of NLO properties at 120°C for more than 160 hr.