Theory and characteristics of holographic polymer dispersed liquid crystal transmission grating with scaffolding morphology

We have performed a detailed characterization of the optical properties of a holographic polymer dispersed liquid crystal (LC) transmission grating with polymer scaffolding morphology, which was fabricated with conventional high-functionality acrylate monomer under low curing intensity. Temporal evolution of the grating formation was investigated, and the amount of phase-separated LC was determined by birefringence investigation. A grating model combined with anisotropic coupled-wave theory yielded good agreement with experimental data without any fitting parameter. The results in this study demonstrate the non droplet scaffolding morphology grating is characterized by a high degree of phase separation (70%), high anisotropy, low scattering loss (<6%), and high diffraction efficiency (95%).     

聚合物光纤用氟树脂材料性能特征

聚合物光纤POF用氟树脂材料首要的性能特征是具有低折射率、无定形、高透明特征,透光率以大于90%为佳,当氟树脂在POF中应用时要求同另一材料有匹配性要求:两者折射率相差0.03以上、膨胀系数及玻璃化温度相近;这种氟树脂不仅是优异的光纤皮材,而且是优异的光纤芯材.氟树脂用作POF芯材时,可降低POF的传输损耗,提高POF的耐温性、POF的传输带宽和POF的耐老化性能等,透明氟树脂是优异的POF芯皮材.     

Vacuum vapour phase polymerised poly(3,4-ethyelendioxythiophene) thin films for use in large-scale electrochromic devices

Large-scale electrochromic devices were manufactured using vacuum vapour phase polymerised (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT). Homogeneous 3,4-ethylenedioxythiophene (EDOT) and water vapour distribution within the large 115 L VPP chamber is paramount for the reproducible synthesis of high conductivity PEDOT thin films. Obtaining these conditions, however, was not trivial. The issue was resolved by synthesising PEDOT under vacuum, however, this altered the dynamics of the polymerisation process. As a result, surfactant addition, monomer and water vapour distribution, monomer and chamber temperature, and polymerisation times were all systematically investigated. Controlling these parameters has resulted in PEDOT with conductivity exceeding 1100 S · cm⁻¹, with a best of 1485 S · cm⁻¹, and electrochromic devices with an optical switch of Δ%Tx ≥ 50%. The resulting high conductivity and optical range are due to long undisrupted PEDOT polymer chains coupled with low levels of oligomers within the matrix.     

液晶型成核剂的合成及对聚乙烯结晶行为的影响--(Ⅰ)液晶型成核剂的合成与表征

以对羟基苯甲酸、对羟基苯甲醚和丙烯酰氯为主要原料,通过逐步酰化反应,合成出了一种具有刚性结构并带有极性基团的乙烯基单体：4-(4-甲氧基)-二酚氧羰基酚丙烯酸酯(ACDHP),并通过自由基引发合成出相应的聚合物PACDHP。利用^1H-NMR和FT-IR对单体和聚合物的化学结构进行了表征。采用DSC、热台偏光显微镜(HS-POM)和TGA对聚合物的相转变温度、液晶态的织构和热稳定性进行了研究。结果表明该热致液晶聚合物的液晶相变温度范围较宽,热稳定性较好．     

一种含薄荷基的手性单体及其聚合物的合成与液晶性能

制备了一种含薄荷基的手性单体及其对应的液晶聚合物,其化学结构、纯度及旋光性质采用红外光谱（FT-IR）、核磁共振（1H-NMR）及旋光仪进行表征,采用差示扫描量热（DSC）与偏光显微镜（POM）等研究了单体与聚合物的介晶性能和相行为,并用热重分析（TGA）表征了聚合物的热稳定性。结果表明,手性单体呈现胆甾相的油丝织构与...     

含硝基噁二唑聚炔的合成及三阶非线性光学性能

设计合成了一种含硝基噁二唑功能基的聚炔材料。通过红外光谱(IR)和核磁共振(1H-NMR)对该聚炔化合物进行了结构表征。利用紫外光谱(UV-vis)和热重分析(TGA)对其性能进行了评价。TGA显示其热稳定性相对于单体有很大提高,UV-vis表明它在500 nm以上长波区吸收很弱。该聚炔化合物的非线性光学性能借助Z-scan技术进行研究,其χ(3)达3.25×10-11(esu)。与含烷基的同类聚炔比较,拉电子基团硝基有效地提高了含噁二唑聚炔的三阶非线性光学性能。     

Preparation of plasma poly(1-isoquinolinecarbonitrile) thin film and its ultrafast nonlinear optical property

How to get a uniform, defect-free, and reproducible conjugated polymer thin films is now becoming the main fabrication problem for the practical application of these materials as the fast switches and modulators in opto-electronic devices. In this research, a novel plasma-polymerized 1-isoquinolinecarbonitrile (PPIQCN) thin film was prepared by plasma polymerization under different glow discharge conditions. The effect of the discharge power on the chemical structure and surface compositions of the deposited PPIQCN films was investigated by Fourier transform infrared (FTIR), UV-Visible absorption spectra and X-ray photoelectron spectroscopy (XPS). The results show that a high retention of the aromatic ring structure of the starting monomer in the deposited plasma films is obtained when a low discharge power of 10 W was used during film formation. In the case of higher discharge power of 30 W, more severe monomer molecular fragmentation can be observed, which results in a decrease in the effective conjugation length of PPIQCN film. The morphology characterized by atomic force microscopy (AFM) indicates that a fine, homogenous PPIQCN film could be obtained under a relatively low discharge power. A femtosecond time-resolved optical Kerr effect technique at a wavelength of 820 nm has been applied to investigate the third-order nonlinearity of the plasma PPIQCN film. For the first time, a non-resonant optical Kerr effect and ultrafast response of the PPIQCN film was observed.     

Design and analysis of a phase modulator based on a metal-polymer-silicon hybrid plasmonic waveguide

A plasmonic-hybrid-waveguide-based optical phase modulator is proposed and analyzed. The field enhancement in the low-index high-nonlinear polymer layer provides nanoscale optical confinement and a fast optical modulation speed. At 2.5 V drive voltage, a π phase shift can be obtained for a 13-μm-long plasmonic waveguide. Because of its small capacitance and parasitic resistance, the modulation bandwidth can reach up to 100 GHz with a low power consumption of ～9 fJ/bit. The plasmonic waveguide is connected to a silicon wire waveguide via an adiabatic taper with a coupling efficiency of ～91%. The phase modulator can find potential applications in optical telecommunication and interconnects.     

Synthesis and characterization of new 3-alkylthiophene copolymer that exhibit orange-red photoluminescence and electroluminescence

Using copolymerization functionalization, a Novel solution-processable π-conjugated 3-alkylthiophene copolymer (molar ratio of monomer 3-octylthiophene (3OT) and 3-(2-ethyl-1-hexyl) thiophene (3EHT) was 1:1) combining electrochemical properties of poly (3-octylthiophene) (P3OT) and poly (3-isooctylthiophene) (P3EHT) was synthesized by FeCl₃-oxidative approach. Characterization of the polymers included FT-IR, NMR, gel permeation chromatography (GPC), thermo-gravimetric analysis (TGA), UV-Vis spectroscopy photoluminescence (PL) and electroluminescence (EL). P3OTEHT depicted excellent solubility in common organic solvents. The optical properties investigations showed that the band-gap energy of P3OTEHT was similar to P3OT (2.43 eV) at 2.45 eV and 6% lower than that of P3EHT in CHCl₃ solution. The emission maxima of P3OTEHT was 50 nm blue-shifted with respect to that of P3OT. However, the PL intensity of P3OTEHT was seven times higher than that of P3OT in film. The turn-on voltage of LED (ITO/P3OTEHT/Ag) devices was approaching to P3OT (5.5 V) at 5.6 V and 1.9 V lower than that of P3EHT. The EL color of P3OTEHT was bright pure orange-red (emission λ_max^EL of 600 nm), meanwhile, the half-wave bandwidth was 70 nm. TGA studies showed that P3OTEHT exhibited very good thermal stabilities, losing 5% of its weight on heating to 300 °C. The results indicate that the P3OTEHT with low band-gap energy, low turn-on voltage, high photoluminescence quantum yield pure EL color and processability, and might be promising polymer materials for applications in polymer light-emitting diodes, light-emitting electrochemical cells and polymer solar cells, etc.     

Polymer‐Stabilized Micropixelated Liquid Crystals with Tunable Optical Properties Fabricated by Double Templating

Self‐organized nano‐ and microstructures of soft materials are attracting considerable attention because most of them are stimuli‐responsive due to their soft nature. In this regard, topological defects in liquid crystals (LCs) are promising not only for self‐assembling colloids and molecules but also for electro‐optical applications such as optical vortex generation. However, there are currently few bottom‐up methods for patterning a large number of defects periodically over a large area. It would be highly desirable to develop more effective techniques for high‐throughput and low‐cost fabrication. Here, a micropixelated LC structure consisting of a square array of topological defects is stabilized by photopolymerization. A polymer network is formed on the structure of a self‐organized template of a nematic liquid crystal (NLC), and this in turn imprints other nonpolymerizable NLC molecules, which maintains their responses to electric field and temperature. Photocuring of specific local regions is used to create a designable template for the reproducible self‐organization of defects. Moreover, a highly diluted polymer network (≈0.1 wt% monomer) exhibits instant on–off switching of the patterns. Beyond the mere stabilization of patterns, these results demonstrate that the incorporation of self‐organized NLC patterns offers some unique and unconventional applications for anisotropic polymer networks.     

Design of omnidirectional high reflectors with quarter-wave dielectric stacks for optical telecommunication bands

A design for omnidirectional high reflectors with quarter-wave dielectric stacks in the optical telecommunication band that uses conventional optical thin-film design theory is described. The omnidirectional bandwidth is derived in units of wavelength and investigated as a function of its high- and low-refractive-index values in the near infrared. The results show that the high refractive index should be larger than 2.26 for an omnidirectional high reflector and that the low refractive index for maximum onmidirectional bandwidth should be approximately 1.5. It is shown that one can design broad-bandwidth omnidirectional high reflectors for S, C, and L bands for optical telecommunication simply by connecting the band edges of omnidirectional high reflectors.     

Polymer Network–Stabilized Liquid Crystals

The fabrication and properties of polymer network–stabilized liquid crystals, formed by polymerization of a small amount of a bifunctional photoreactive monomer dissolved in a liquid‐crystalline phase, are reviewed. The polymer network morphology is strongly related to preparation conditions such as monomer content, polymerization temperature, and ultraviolet (UV) curing conditions. The transfer of anisotropic liquid‐crystalline order onto the network is discussed in detail. The electro‐optical performance of network‐stabilized nematics, cholesterics, and ferroelectric smectics is largely dependent on the morphology of the network, as will be demonstrated with an emphasis laid on polymer‐stabilized cholesteric textures (PSCTs). A general correlation between polymerization conditions, network morphology, and electro‐optical behavior will be outlined and aspects concerning applications discussed.     

In situ spectroscopic study of the electropolymerization and properties of polyterthiophene

The electrochemical polymerization of terthiophene has been studied using time resolvedin situ UV-visible transmission spectroscopy. The similarity of monomer and polymer oxidation potentials allows one to deposit partially or fully doped polymer. Both coulometric and spectroscopic data show that the level of doping increases with polymerization potential up to about 1.1 V, at which point it attains its maximum value of one positive charge per four rings, as for the parent thiophene. At the relatively low polymerization potentials employed, incompletely polymerized material is trapped within the polymer film. Direct evidence for the presence of trapped monomer is the disappearance of a peak at 355 nm upon the application of positive potentials to a film transferred to monomer-free background electrolyte. Spectroscopic and coulometric assay of these species shows that they constitute an appreciable fraction (ca. 20%) of the immobilized material at low polymerization potentials. The ability of these species to remain unpolymerized decreases with increasing polymerization potential. In all cases, they are polymerized during subsequent potential cycling in the range 0.0–1.15V. The redox composition of the polymer, estimated using optical data, shows non-Nernstian behaviour.     

Characterization of a polymer film optical fiber hydrophone for use in the range 1 to 20 MHz: a comparison with PVDF needle and membrane hydrophones

A small aperture wideband ultrasonic optical fiber hydrophone is described. The transduction mechanism is based on the detection of acoustically induced changes in the optical thickness of a 25-mum thick parylene polymer film acting as a low finesse Fabry Perot (FP) interferometer that is deposited directly onto the end of a single mode optical fiber. The acoustic performance compares favorably with that of PVDF needle and membrane hydrophones with a peak noise-equivalent-pressure (without signal averaging) of 10 kPa over a 25-MHz measurement bandwidth, a wideband response to 20 MHz, and a near omnidirectional performance at 10 MHz. The dynamic range was 60 dB with an upper limit of linear detection of 11 MPa and a temporal stability of <5% over a period of 20 h. The hydrophone can also measure temperature changes with a resolution of 0.065 degrees C, offering the prospect of making simultaneous acoustic pressure and temperature measurements. The transduction parameters of the FP sensing element were measured, yielding an ultrasonic acoustic phase sensitivity of 0.075 rad/MPa and a temperature phase sensitivity of 0.077 rad/ degrees C. The ability to achieve high acoustic sensitivity with small element sizes and to repeatably fabricate rugged sensor downleads using polymer deposition techniques suggests that this type of hydrophone can provide a practical alternative to piezoelectric hydrophone technology.     

Scanning probe microscopy based on magnetoresistive sensing

Integrated sensors are essential for scanning probe microscopy (SPM) based systems that employ arrays of microcantilevers for high throughput. Common integrated sensors, such as piezoresistive, piezoelectric, capacitive and thermoelectric sensors, suffer from low bandwidth and/or low resolution. In this paper, a novel magnetoresistive-sensor-based scanning probe microscopy (MR-SPM) technique is presented. The principle of MR-SPM is first demonstrated using experiments with magnetic cantilevers and commercial MR sensors. A new cantilever design tailored to MR-SPM is then presented and micromagnetic simulations are employed to evaluate the achievable resolution. A remarkable resolution of 0.84?? over a bandwidth of 1?MHz is estimated, which would significantly outperform state-of-the-art optical deflection sensors. Due to its combination of high resolution at high bandwidth, and its amenability to integration in probe arrays, MR-SPM holds great promise for low-cost, high-throughput SPM.     

含对苯二甲酸双(对甲氧基苯)酯液晶基元聚噻吩的合成

从设计合成单体噻吩取代对苯二甲酸双(对甲氧基苯)酯入手,以FeCl3为催化剂,CHCl3为溶剂,合成了一种新型以聚噻吩为共轭主链的共轭聚合物.利用核磁共振(1H-NMR),红外光谱(IR)等方法表征了单体和聚合物的结构.利用差示扫描量热仪(DSC)、带热台的偏光显微镜(POM)、紫外光谱(UV)和荧光光谱(PL)研究了聚合物液晶性和光学性能.结果表明,该聚合物为无规聚合物.通过偏光显微镜观察,单体具有向列型液晶态纹影织构,而由于大体积刚性侧基破坏了聚合物的液晶性,聚合物分解温度之前未观察到该聚合物有明显的双折射现象.     

Shift-invariant real-time edge-enhanced VanderLugt correlator using video-rate compatible photorefractive polymer

We demonstrated a real-time shift-invariant VanderLugt correlator (VLC). The VLC was implemented with a 37 microm thick bis-triarylamine side-chain polymer matrix photorefractive (PR) polymer composite operating at 532 nm wavelength. Correlation selectivity was enhanced by real-time edge enhancement. The advantage of the VLC is that its architecture allows overcoming the PR material response speed. A correlator of this type enables a fast shift-invariant search of a large optical image database. A high degree of shift invariance in our correlator was possible because of the material thickness. The angular bandwidth of this material was measured experimentally in a degenerate four-wave mixing setup, and it was found to be in a very good agreement with the theory.     

丙烯基醚-丙烯酸酯杂化单体的合成及光聚合动力学研究

自由基光聚合和阳离子光聚合技术中各自存在着固有不足之处，诸如挥发性强，氧气阻聚作用大，收缩率高或者固化速度慢，水分影响严重等。 杂化光聚合体系是一种可以改善这些不足的方法，它可以分为混合杂化体系和杂化单体体系两种。其中杂化单体是指包含两种不同反应机理的活性基团，并通过化学键连结的单体，这种结构将改变两种官能团的光聚合动力学性质，并且使通过两种光聚合机理形成的聚合物成为均匀一致的、通过化学键相连的互穿网络结构，从而提高其机械物理性能。 本文合成了一种新型的丙烯基醚-丙烯酸酯杂化单体-丙烯氧基丙氧基丙烯酸酯（PPA），并应用实时变换傅立叶红外光谱法（RT—FTIK）对其进行了光聚合动力学研究。结果表明，在以硫锚盐为光引发剂时，这种杂化单体可以有效进行杂化光聚合反应，丙烯基醚和丙烯酸酯双键都显示出了较快的反应速度和较高的最终转化率。与混合杂化体系相比，每种基团的反应动力学性质都得到了促进，同时这种杂化单体结构还降低了羟基对于烯基醚基团光聚合的影响。这将为开发新型的光聚合活性单体开创新的途径和方法。     

A free-standing poly(9-(6-(thiophene-3-yl)hexyl)-9H-carbazole) films: electrosyntheses from a novel carbazole monomer bearing thiophene moiety

The pursuit for the electrosyntheses of high quality polycarbazole (PCz) films is a great challenge for the application of polycabazoles. The incorporation of thiophene unit into carbazole monomer might result in a novel polymer having both the advantages of polythiophene and polycarbazole. As expected in this paper, a novel conducting polymer, free-standing poly(9-(6-(thiophene-3-yl)hexyl)-9H-carbazole) (PTh-H-Cz) films with electrical conductivity of 7.8 S/cm, were synthesized electrochemically by direct anodic oxidation of a novel carbazole monomer, 9-(6-(thiophene-3-yl)hexyl)-9H-carbazole (Th-H-Cz), in boron trifluoride diethyl etherate (BFEE) solution. Incorporation of thiophene unit into carbazole monomer as a pendant led to the electrodeposition of high quality PCz films with metallic shine. Fluorescence spectral study revealed that as-formed polymer film in solid state was a good blue light emitter with strong emission at about 410 nm. This high quality free-standing PTh-H-Cz film will facilitate their potential applications as blue-light-emitting materials in organic light-emitting dioxide.     

聚合物光纤及其应用

本文综述国内外聚合物光纤的最新进展 ,介绍降低聚合物光纤损耗的氘化和氟化的方法 ,提出宽带的梯度折射率聚合物光纤 .分析聚合物的光学特性 ,报道功能聚合物光纤、聚合物光纤的无源和有源器件的研究 .