改性血红蛋白诱导手性聚苯胺的合成

The synthesis of chiral polyaniline (PANI) induced by modified hemoglobin (Hb) was profoundly explored for the first time. Results revealed that after being separated, inactivated or immobilized, Hb can still induce the formation of chiral PANI successfully, suggesting that Hb can be used as the chiral inducers regardless of harsh reaction conditions. By examining the properties of PANI induced by modified Hb, it was found that Hb(inactivated)-PANI possessed excellent chirality, stability, and crystalline structure. The globin separated from Hb was demonstrated to have the ability of inducing the production of chiral PANI whereas the hematin from Hb had no capacity to direct enantio specificity for the PANI chains. Results indicated that Hb(immobilized)-PANI exhibited poor yield, doping state, and crystalline structure, indicating that the immobilization of Hb by entrapment was not bene cial to the polymerization reaction. Results also showed that the structure of Hb may have significant effects on the morphologies of chiral PANI.     

Emergence of Paramagnetism in Organic Macromolecules during Synthesis

Paramagnetism in polyaniline can be generated during synthesis if cerium (IV) ammonium nitrate (CAN) is used as a polymerizing (oxidizing) agent. During the reaction, in situ formation of Ce³⁺ ions are doped in the spherical polyaniline particles and show paramagnetic behavior throughout the experimental temperature range (400–1.9 K). The result indicated that the Ce³⁺ ions covalently functionalized with the chain nitrogen of the polyaniline.     

Synthesis,Characterization, and AC Conductivity of Polyaniline/Selenium Composites

This study reports structural and thermal properties and temperature-dependent alternating current (AC) conductivity of polyaniline/selenium (PANI/Se) composites in emeraldine salt form prepared by a chemical polymerization method. Fourier transform infrared spectroscopy showed that the doping process significantly affected the N-H bond in PANI chain. The free energy change, which was calculated from the Langmuir adsorption isotherm, showed that Se was electrostatically adsorbed on PANI molecules. From the scanning electron microscopy images it was determined that morphological changes caused by the doping process on PANI surface could affect conductivity. Thermal analysis, which was performed with differential scanning calorimetry, showed that the addition of Se increased the degradation temperature of PANI. Depending on the doping level, significant increase was observed in the AC conductivity of PANI, approximately 11, 13, and 17 times for 300, 350, and 400 K temperatures respectively.     

紫外光控制的金属硫化物/聚苯胺p-n结及其在光敏传感器中的应用

设计了由金属硫化物/聚苯胺p-n异质结和紫外光敏材料氧化锌所组成的光敏传感器,通过紫外光照外接氧化锌层来控制金属硫化物/聚苯胺p-n结的耗尽区厚度。与其他报道的光敏材料不同的是,其他光敏材料在紫外光照射下光电导会增加,而该光敏传感器在紫外光照射下光电导会减少。     

Synthesis and Characterization of Conductive Polyaniline Nanoparticles Through Ultrasonic Assisted Inverse Microemulsion Polymerization

Polyaniline (PANI) nanoparticles were prepared through ultrasonic assisted inverse microemulsion polymerization method. Polymerization of aniline was confined to a nanoreactor named water pool surrounded by surfactant molecules in the apolar continuous phase. The size of the PANI nanoparticles decreases with the decrease of the value. The spherical nanoparticles (10–50 nm) can further form the uniform submicrometer aggregates with a size of 200 400 nm induced by ethanol, and the size of the aggregate decreases with the decrease of the value. The morphology of aggregates as well as aggregation behavior of PANI nanoparticles were characterized by TEM. The polymerization rate, UV–vis absorption spectra, FTIR spectra, XRD, as well as the conductivity were examined at different [water]/[surfactant] molar ratio, i.e. value. Ultrasound enhances the polymerization rate of aniline that is usually very slow under conventional stirring in inverse microemulsion and contributes to produce spherical nanoparticles. Also, ultrasound irradiation promotes the diffusion of HCl molecules and improves the degree of doping. Polymerization of aniline occurred in the confined nanoreactor in microemulsion and strengthens the hydrogen-bonding of amine and imine of PANI molecular chains, which improves the degree of crystallinity. The conductivity of obtained PANI is in the magnitude of 10^-1 S cm^-1, and is changed with value.     

Preparation and Characterization of the Polyaniline Nanocomposites with Electricity/Magnetic Properties

Three kinds of magnetic particle (water-based NiZn ferrite fluid, water-based Fe₃O₄ magnetic fluid, and silicon-oil-based Fe₃O₄ magnetic fluid)/polyaniline nanocomposites were prepared in this study. The samples, after drying and grinding, were characterized by infrared spectrometry (IR), X-ray diffraction (XRD), and UV-vis, scanning electron microscope (SEM); their electromagnetic properties were also measured. The conductivitiy of the resulting water-based NiZn ferrite/polyaniline nanocomposites (WBNiZnFe/PA) was the greatest, reaching 0.094 s/cm, while the conductivitiy for water-based Fe₃O₄ magnetic particle/polyaniline nanocomposites (WBFe₃O₄/PA) was the lowest, reaching only 0.068 s/cm. The saturation magnetization for WBFe₃O₄/PA was the greatest, being 1.5 emu/g, while the saturation magnetization for WBNiZnFe/PA was the lowest, being only 0.8 emu/g. The coercivity of all magnetic particle/polyaniline nanocomposites was about He = 200 Oe.     

聚苯胺与还原石墨烯复合材料的微波吸收性能

采用化学氧化法制备聚苯胺与还原石墨烯复合材料。复合材料的结构、晶型和电磁参数分别通过X射线衍射仪及HP8722ES型矢量网络分析仪进行表征、测试与分析。结果表明,同聚苯胺相比,聚苯胺与还原石墨烯复合材料的介电损耗明显增加。而且在复合材料中,石墨烯的含量越大,材料的微波吸收性能越好,在频率波段（9.5~13.4GHz）反射损耗均小于-10 dB,并在频率为11.2 GHz时达到最大反射损耗-29.69 dB。聚苯胺与还原石墨烯的复合使得材料的载流子迁移率变大,吸波特性得到改善。     

Controllable Synthesis of Upconversion Nanophosphors toward Scale-Up Productions

Upconversion nanophosphors (UCNPs) are considered as an important synthesis arm within biomedical and energy sectors due to their unique optical characteristics, which can convert near-infrared light into higher energy emissions. However, key challenges, cost, compatibility of the materials, etc. have to be taken into serious consideration to transform this in-lab UCNPs technology into scale-up production for wider commercial needs. This review highlights the fundamental concepts of synthetic approaches for UCNPs and recaps recent advances in terms of large-scale production. A number of typical synthesis routes in both batch and continuous processes are reviewed, alongside their limitations and potential improvements when being considered for mass production. By discussing and exploiting the technical compacity for the potential synthetic trends, key challenges, and expectations of future synthesis methods for UCNPs are also outlined.     

Synthesis and Characterization of La‐Doped Fe3O4‐Polyaniline Magnetic Response Nanocomposites

Lanathum (La)‐doped Fe₃O₄ magnetic nanoparticles were prepared in aqueous solution at room temperature, then La‐doped Fe₃O₄‐polyaniline (PANI) nanocomposites containing a dispersion of La‐doped Fe₃O₄ nanoparticles were synthesized via in‐situ polymerization of aniline monomer. The structure and properties of the synthesized samples were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometry (ICPAES), and a vibrating sample magnetometer (VSM). The resulting particles of La‐doped Fe₃O₄ and La‐doped Fe₃O₄‐PANI were almost spherical with diameters ranging from 15 to 25 nm and 25 to 85 nm, respectively. The La‐doped Fe₃O₄‐PANI composite presented core‐shell structures; polyaniline covered the La‐doped Fe₃O₄ completely. The specific saturation magnetization of La‐doped Fe₃O₄‐PANI depended on the starting material of La‐doped Fe₃O_4. It increased with increasing amounts of La and Fe₃O₄ content.     

Emulsion Polymerization: A New Approach to Prepare Graphite Oxide Coated with Polyaniline

A novel approach is used to synthesize graphite oxide (GO) coated with polyaniline (PANI) by in-situ emulsion polymerization. The dispersion behavior of exfoliated graphite oxide in aqueous solution under ultrasonic vibration is investigated by atomic force microscopy (AFM). Strong interactions owing to hydrogen bonds and electrostatic effects between PANI and GO surfaces are revealed by FT-IR and Raman spectra. Scanning electron microscopy (SEM) further confirms that GO is well-coated with PANI, and a uniform appearance is seen. The increased crystallinity of PANI/GO is characterized by X-ray diffraction (XRD). The product is also characterized by thermogravimetry(TG) and electrical conductivity.     

盐酸掺杂聚苯胺薄膜的隐身性能

将本征态聚苯胺的N-甲基吡咯烷酮溶液浇铸在玻璃基板上,烘干脱去基板后得到自支持本征态聚苯胺薄膜,用HCl气体对薄膜进行掺杂,通过控制掺杂时间来控制掺杂浓度.红外反射率测试结果表明:在大气窗口内,掺杂浓度较低时,薄膜的红外反射率随着掺杂浓度的提高而增加;到达一定掺杂浓度后,反射率会随着掺杂浓度的提高有所降低,最终趋于稳定...     

Spectroscopic Studies on Threonine Doped Polyaniline Composites

The structural and magnetic properties of polyaniline (PANI)- and threonine (T)-doped polyaniline composites were characterized by using FTIR, UV-Vis, and electron paramagnetic resonance (EPR) spectroscopic techniques. The FTIR, UV-Vis, and X-band EPR spectra were recorded for PANI- and threonine-doped polyaniline (PANI-T) composites. The increased intensity of the IR bands in PANI-T composites is due to the increasing dopant concentration. The observed red shift corresponding to the N-H ··· N mode indicates the hydrogen bond formation in between the PANI and threonine molecule. The observed decrease in spectral intensity of the UV-Vis spectrum of the PANI-T composite confirms the occurrence of the protonation at the imine nitrogen sites. The EPR parameters such as line width, g factor, line asymmetry parameter, signal intensity, and spin concentration values were estimated. The EPR spectrum of PANI clearly indicates the presence of unpaired polaron. The EPR signal intensity and spin concentration values decrease with increasing dopant concentration, which reveals the polaron to bipolaron formation in PANI-T composites. EPR lineshape analysis showed that the absorption profile was Gaussian shape. The Gaussian-shaped line is generally due to the dipole–dipole interactions in the PANI and PANI-T composites. The line asymmetry parameter and g values indicated the isotropic nature of PANI and PANI-T composites.     

Nonlinear Eulerian Analysis of Harmonic Generation in Traveling-Wave Tubes

A third-order nonlinear Eulerian hydrodynamic formulation was developed for the analysis of harmonic generation in helix traveling-wave tubes. The analysis was simple and computationally fast compared to Lagrangian analysis, and contrary to the existing belief, the theory could as well demonstrate the saturation behavior of the device. The performance of the theory was also found to be in close agreement with that of the Lagrangian analysis. The theory is expected to be useful as a first-hand design and simulation tool for microwave and millimetric wave traveling-wave tubes.     

AOT微乳体系中纳米银的可控合成及其紫外-可见光谱研究

在以琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂、环己烷为连续相形成的W/O型微乳体系中,用增溶于微乳液水核中的AgNO₃为银源、水合肼为还原剂制备了纳米银溶胶,利用UV-Vis光谱分析了AgNO₃的浓度、AOT的浓度、还原剂的种类和水与表面活性剂的物质的量比(W)等参数对形成粒子数量及平均粒径的影响,为纳米银粒子的可控合成和纳米银的UV-Vis光谱解析提供了新的依据。研究表明,适当增大AgNO₃的浓度,有利于形成粒径较小的纳米银粒子;W值增大,形成粒子的平均粒径和粒子数量明显增加。和NaBH₄相比,水合肼在反胶束中的溶解性能较好,有利于微乳液反胶束中Ag+的还原。增大AOT的浓度,在一定范围内胶束对反应物的增溶能力增强,胶束的半径也相应减小,有利于形成数量较多、平均粒径较小的纳米银粒子。     

Study of a Waveguide CO_2 Laser with Two Parallel Tubes

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Particles with Magnetic Patches: Synthesis,Morphology Control,and Assembly

The concept of patchy particles is revolutionizing the research field of colloidal assembly, by the design of particles whose surface is purposely patterned to promote attractive interactions with their neighbors in limited number, and in privileged and programmed directions. The idea of magnetic patches makes it possible to imagine assemblies not only spontaneous by simple magnetic coupling but also triggered and canceled at will due to external magnetic fields. This review shows that studies published until now mainly deal with particles with a single magnetic patch, often called Janus particles. The very diverse synthetic routes have been brought together into four main strategies, covering the size range from 100 nm to 100 µm. Their assembly capacity is described both from experimental and simulation viewpoints. The orientation of the magnetic moment of the patch and its decentering extent with respect to the particle are the key parameters for controlling the morphology of clusters, loops, staggered chains, double chains, helices, microtubes, etc. The review offers some perspectives to generalize these studies to multipatch particles, examples of which are still too rare, and to make assemblies sustainable, especially after the removal of the structuring magnetic fields.     

Single/Double Soft-Templates Involved Synthesis of Polyaniline Blends: Interfacial Polymerization and Characterization by AC Impedance Analysis

Polyaniline (PANI) blends with single and double soft-templates (polyvinylpyrrolidone – PVP and/or sodium dodecylbenzenesulfonate – SDBS) were synthesized using interfacial polymerization. Fourier transform infrared (FTIR) spectral study confirmed blend formation. Polyaniline-polyvinylpyrrolidone (PANI-PVP) blend had submicron aggregates of 50–150 nm nanoparticles while PANI-SDBS blend had extensively agglomerated large size flakes/grains. Polyaniline-polyvinylpyrrolidone-sodium dodecylbenzenesulfonate (PANI-PVP-SDBS) blend had larger aggregates, besides significant number of smaller grains. Alternating current (AC) impedance analysis was performed to determine their electrical properties. At room temperature the AC conductivity of the blend materials was in the increasing order, PANI < PANI-PVP < PANI-SDBS < PANI-PVP-SDBS. But other parameters, like critical frequency and power law index s, exhibited a decreasing trend in the blend materials. With regard to frequency-dependence, all the materials showed constant AC conductivity at low frequencies, but at higher frequencies and at higher temperatures conductivity increased gradually. The obeyance of a universal power law and the range of s values (0.12 < s < 0.78) suggested a correlated barrier hopping (CBH) mechanism for AC conductivity of all the materials. The trends in electrical properties that were characteristic of the role of single/double soft-templates were explained in terms of improved π-electron delocalization and hopping mechanism.     

水热法制备形貌可控的ZnMoO4微晶及其光致发光性能

以Zn(Ac)2和(NH4)6Mo7O24.4H2O为原料,分别以CTAB、SDS、PVP-K30作为辅助剂,采用水热法合成了不同形貌和结构的ZnMoO4微晶。使用X射线衍射(XRD)、扫描电镜(SEM)及光致发光光谱(PL)等分析手段对所得材料的结构、形貌及发光性能进行了分析和表征。测试结果表明:通过改变辅助剂的种类、用量和反应时间可以合成形貌可控的ZnMoO4微晶,不同形貌的样品发光强度不同,但发射中心均在565 nm左右。     

A Study on Hall Voltage and Electrical Resistivity of Doped Conducting Polyaniline

We report the electrical resistivity of HCl doped polyaniline in the temperature range 77 T 300 K. A maximum is obtained in the conductivity versus concentration of HCl curve at 3(N) HCl. The resistivity of the sample has been observed to show a decreasing trend with increase in temperature. The resistivity obeys the Mott variable range hopping theory. The Mott characteristic temperature (T _Mott) is very low in this sample compared to other studies. The Hall voltages have been found to be negative. The Hall coefficient, carrier concentration, and density of states have been determined from Hall measurement. From the conductivity versus temperature plot, different physical quantities such as localisation length and molecular vibrational frequency have been determined.