Conductive Cotton Prepared by Polyaniline In Situ Polymerization Using Laccase

The high-redox-potential catalyst laccase, isolated from Aspergillus, was first used as a biocatalyst in the oxidative polymerization of water-soluble conductive polyaniline, and then conductive cotton was prepared by in situ polymerization under the same conditions. The polymerization of aniline was performed in a water dispersion of sodium dodecylbenzenesulfonate (SDBS) micellar solution with atmospheric oxygen serving as the oxidizing agent. This method is ecologically clean and permits a greater degree of control over the kinetics of the reaction. The conditions for polyaniline synthesis were optimized. Characterizations of the conducting polyaniline and cotton were carried out using Fourier transform infrared spectroscopy, UV–vis spectroscopy, cyclic voltammetry, the fabric induction electrostatic tester, and the far-field EMC shielding effectiveness test fixture.     

乳液法制备掺杂聚苯胺的微观结构研究

在众多的导电聚合物中,聚苯胺(PAn)被认为是最具应用前景的导电聚合物^[1].本征态PAn的电导率约10^-13S/cm数量级,呈电绝缘性.当用质子酸对PAn掺杂后,电导率达到5～10S/cm,可实现从绝缘体到导体的转变.     

Polyaniline Nanotubes Prepared by One-Step Synergistic Polymerization of Aniline and Acrylic Acid

The electrochemical property of electrode materials greatly depends on their morphologies. This report introduces a novel and facile synthesis method for polyaniline (PANI) nanotubes from one-step synergistic polymerization of aniline and acrylic acid in an aqueous solution induced by the addition of ammonium persulfate (APS). The molar ratio of aniline to AA (\begin{document}$X_{\rm{ani/AA}}$\end{document}) is found to have great influence on the morphology of the produced PANI. Hollow PANI nanotubes with an average inner diameter of 80 nm and outer diameter of 180 nm can be mainly produced when \begin{document}$X_{\rm{ani/AA}}$\end{document} is not higher than 1. The electrochemical properties of the prepared PANI nanotubes have been investigated using a three-electrode system. The specific capacitance of PANI nanotubes can reach 436 F/g at a current density of 0.5 A/g in 1 mol/L H\begin{document}$_2$\end{document}SO\begin{document}$_4$\end{document} solution. Furthermore, the specific capacitance of the PANI nanotube maintains 89.2% after 500 charging/discharging cycles at a current density of 0.5 A/g, indicating a good cycling stability.     

化学聚合法制备电容器用聚苯胺

采用化学聚合法制备电容器用聚苯胺,研究了不同的掺杂剂对聚苯胺(Pan)电导率的影响,并利用TGA、FT-IR等分析手段对聚苯胺的热老化性质进行研究,研究了乳液法产物的二次掺杂现象,并把萃取液涂布于铝箔表面制成固体电容器,结果表明这种聚苯胺应用于固体电容器是可行的。     

基体表面性质对原位聚合沉积导电聚苯胺薄膜性能的影响

以水溶性高分子聚乙烯吡咯烷酮(PVP)为空间稳定剂,在经十八烷基三氯硅烷(OTS)改性的玻璃表面进行原位聚合,沉积得到导电聚苯胺(PANI)薄膜。采用表面界面张力仪、扫描电镜(SEM)、紫外可见光谱(UV-Vis)、红外光谱(FT-IR)、四探针电导率测试仪及光学显微镜对不同基体表面的接触角、PANI膜的形貌、厚度、结构、导电性及其在亲/憎水表面选择性沉积性能进行测定。结果表明:OTS对玻璃表面的改性促进了聚苯胺的沉积且提高了薄膜厚度,薄膜饱和厚度达到200 nm;缩短了溶液中苯胺分散聚合的诱导期,反应速率增大;与未改性玻璃表面沉积的薄膜相比,改性的玻璃表面得到的聚苯胺薄膜更加细密均匀,聚苯胺颗粒尺寸小,堆积紧密;薄膜的电导率达到7.5×10-3S/cm;OTS改性对基体表面的薄膜生长和溶液中的苯胺聚合具有催化作用。     

APS/NaClO 复合氧化剂对乳液法合成聚苯胺的微观形貌及其电化学性能的影响

采用乳液法, 以过硫酸铵(APS)和次氯酸钠(NaClO)为复合氧化剂合成导电聚苯胺(PANI). 考察了NaClO 的加入与否对PANI 微观形貌与电化学性能(循环伏安和电导率)的影响, 以及APS、乳化剂十二烷基苯磺酸钠(SDBS)和NaClO的用量对PANI 电化学性能的影响. 结果表明: NaClO 的加入对PANI 的微观取向结构具有重要的影响. 与采用单一APS 合成的PANI 相比, 复合氧化剂合成的PANI 具有较高的循环伏安峰电流以及更加优异的电导率(约为前者的2.6倍). 当苯胺(An)与APS 的物质的量比(n_An:n_APS )为8:7, An 与SDBS 的物质的量比(n_An:n_SDBS )为10:4, NaClO 用量为5%(质量分数)时, PANI 的各项性能指标达到最好; 紫外可见光谱和红外光谱的表征结果表明, 采用复合氧化剂并未对PANI 的分子结构产生明显的影响.     

PMMA-AES Blends Prepared by in situ Polymerization

Blends of poly(methyl methacrylate) (PMMA) and poly(acrylonitrile-g-(ethylene-co-propylene-co-diene)-g-styrene) (AES) were prepared by in situ polymerization. AES, a commercial elastomer obtained by radical copolymerization of styrene and acrylonitrile in the presence of ethylene-propylene-diene terpolymer (EPDM), was dissolved in methyl methacrylate and the in situ polymerization was conducted at 60 °C. The blends were characterized by CHN analysis, infrared spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (¹³C NMR), dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM). These blends are immiscible and present complex phase behavior. Selective extraction of the blends’ components showed that a fraction of the material is crosslinked and grafting reactions on EPDM chains take place during MMA polymerization. Syndiotactic PMMA was obtained in the presence of AES and this syndiotactic-specificity increased with increasing amount of AES. The morphology of polymerized specimens showed irregular domains of elastomeric phase and in some cases inclusions of PMMA could be observed.     

Response Characteristics of a Glucose Electrode with a Sensing Membrane Prepared by Plasma Polymerization

A glucose electrode was composed of a dissolved oxygen electrode and an immobilized glucose oxidase membrane prepared by plasma polymerization of propargyl alcohol as a monomer. Fairly good precision of the electrode response to sample solutions was obtained by measurements using the steady-state method or the reaction rate method. Activity of the glucose oxidase immobilized within the membrane and mounted on the electrode lasted for 50 consecutive measurements over 5 days, and, if the membrane was stored in a buffer solution of pH 7.0 at a temperature of 0°C, the activity was preserved for more than 2 months. Such immobilization of the glucose oxidase with the plasma polymer effectively suppressed interference from Cu²⁺ions, which would seriously interrupt oxidation of the glucose in homogeneous solutions, in the sample solutions.     

Synthesis of Aminooxy End-functionalized pNIPAAm by RAFT Polymerization for Protein and Polysaccharide Conjugation

A Boc-protected aminooxy end-functionalized poly(N-isopropylacrylamide) (pNIPAAm) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The monomer was polymerized in the presence of a Boc-protected aminooxy trithiocarbonate chain transfer agent (CTA) utilizing 2,2'-azobis(2-isobutyronitrile) (AIBN) as the initiator in DMF at 70 °C. The final polymer had a number-average molecular weight (M(n)) of 4,200 Da as determined by (1)H NMR spectroscopy and a narrow polydispersity index (1.14) by gel permeation chromatography (GPC). The Boc group was removed, and the polymer was then incubated with N(ε)-levulinyl lysine-modified bovine serum albumin (BSA). Gel electrophoresis confirmed that the conjugation was successful. The aminooxy end-functionalized pNIPAAm was also immobilized on a gold surface after reduction of the trithiocarbonate end-group. The pNIPAAm surface was then incubated with an aldehyde-modified heparin to yield the polysaccharide-functionalized surface. All surface modifications were monitored by FT-IR spectroscopy.     

Synthesis of CdSe–Poly(N‐vinylcarbazole) Nanocomposite by Atom Transfer Radical Polymerization for Potential Optoelectronic Applications

A hybrid inorganic–polymer nanocomposite using CdSe nanocrystals with high electron mobility has been successfully synthesized by atom transfer radical polymerization (ATRP). First the hydroxyl‐coated CdSe nanoparticles (i.e., CdSe–OH) were prepared via a wet chemical route. A polymerization initiator was then prepared for ATRP of N‐vinylcarbazole. FT‐IR, ¹H NMR, and XRD analyses confirmed the successful synthesis of CdSe–poly(N‐vinylcarbazole) (PVK) nanohybrid. UV–Vis spectra and photoluminescence data revealed that grafting of PVK onto the surface of CdSe nanocrystals would reduce the band gap of PVK and cause the red shift of emission peak. TEM and SEM micrographs exhibited CdSe nanoparticles that were well‐coated with PVK polymer.

     

Structure and Electronic Properties of Extended Chromophores for Applications in Second-Order Nonlinear Optics

A structural and theoretical analysis of new 2-[(4-phenylazo)phenyl] benzoxazole chromophores of potential interest in the field of second-order nonlinear optics is presented. Computations predict comparatively high hyperpolarizabilities for most of the compounds in their equilibrium nuclear configuration, with a significant dependence upon some conformational degrees of freedom and independence upon some others. This behavior is rationalized in the frame of the two-level model and sheds light on the conjugation pattern of these new chromophores.     

Role of Plasma Parameters on the Conjugated Structure Retention in Polyaniline Thin Film

The role of plasma parameters on the film characteristics is investigated on polyaniline thin film deposited by radio frequency (RF) plasma polymerization. A series of un-doped and iodine doped polyaniline thin films are prepared by RF discharge operating at 13.56?MHz with different discharge powers and pressure variation from 0.1 to 0.05?mbar and variation in deposition time from 20 to 40?min. A good thin film is found with a power ranging from 9?W (?28?V self bias) to 20?W (?65?V self bias) at 0.1?mbar pressure which is confirmed by fourier transform infra-red spectroscopy showing the retention of aromatic rings. In addition, iodine doping is carried out with 9?W power and 0.1?mbar pressure. The characterization of process plasma is done using Langmuir probe diagnostics and optical emission spectroscopy. A correlation has been established between film characteristics and plasma properties investigated using optical emission spectroscopy and Langmuir probe analysis. Emphasis has been given on the study of the influence of plasma parameters, particularly of the electron energy distribution function on the quality of conjugated plasma polymerized aniline film.     

光诱导聚合制备聚噻吩/二氧化钛复合粒子的结构及光催化性能

通过光诱导噻吩在TiO2的氯仿悬浮液中聚合反应,制备了聚噻吩/二氧化钛(PTh/TiO2)复合粒子,并采用比表面积分析仪、扫描电子显微镜、粒径分析仪、X射线光电子能谱、紫外-可见漫反射光谱和红外光谱对复合粒子进行了表征.结果表明,PTh/TiO2复合粒子上的聚噻吩骨架中S原子与TiO2粒子间存在强相互作用,该复合粒子对...     

掺杂率对乳液聚合制备聚苯胺结构性能的影响

对乳液聚合的十二烷基苯磺酸(DBSA)掺杂聚苯胺(PAn)进行不同pH值溶液浸泡处理。采用元素分析、红外光谱分析、X射线衍射及热失重分析等手段，研究了不同掺杂率对PAn结构性能以及PAn在普通有机溶剂中的溶解性能和导电性能的影响。结果表明：随DBSA掺杂率的增加，PAn的电导率及其在三氯甲烷中的溶解度增加，带有烷基长链的DBSA使PAn形成以DBSA为间隔的有序层状结构；而且合成的PAn-DBSA热稳定性良好。     

聚合时间对染料敏化太阳能电池中聚苯胺对电极结构和性能的影响

采用恒电压方法, 以掺杂氟的SnO₂ (FTO)导电玻璃为基底, 采用不同的聚合时间制备SO₄^2?掺杂的聚苯胺对电极(PANI CEs). 利用扫描电子显微镜(SEM)、紫外-可见(UV-Vis)吸收光谱、循环伏安法(CV)和电化学阻抗谱(EIS)等技术详细研究了聚合时间对PANI CEs的表面形貌、结构(如掺杂度、共轭性、氧化态等)和对I^?/I^3?的催化活性的影响. SEM结果表明PANI在FTO上的生长分两个阶段. 适当增加聚合时间可以增加PANI CEs的比表面积, 为催化I^?/I^3?反应提供更多的活性位点, 同时聚苯胺链的共轭性、半氧化态聚苯胺(EB)结构的含量和对阴离子SO₄^2?的掺杂度会随着增加, 进而PANI 的导电率也逐渐增大. 然而, 聚合时间过长会引起薄膜厚度的增加和氧化结构的过多, 使PANI CEs的导电率降低, 电子在PANI 薄膜中的传输阻抗增加, 进而影响其对I^?/I^3?的催化性能. 聚合时间为300 s 时制备出的PANI 薄膜作为染料敏化太阳能电池(DSSCs)对电极和以D149 为染料时, 获得的最高电池光电转换效率为5.30%, 可达到基于Pt 对电极电池效率的88%. 因此, 通过电化学方法制备的PANI CEs有望代替贵金属Pt CEs用于DSSCs中.     

Chain Orientation in Polyethylene Fibers Prepared by Ethylene Nanoextrusion Polymerization

Summary: Ethylene nanoextrusion polymerization has been demonstrated to be a novel nanofabrication concept for the preparation of polyethylene (PE) fibers directly from ethylene monomers without any post‐processing procedures. For PE fibers, chain orientation is a critical parameter that affects performance and application of the fibrous materials. In this communication, we report an investigation on chain orientation in PE fibrous samples prepared through nanoextrusion polymerization using a two‐dimensional wide angle X‐ray diffraction (2D WAXRD) technique. Two types of fibrous samples, including individual microfibers and microfiber aggregates, were sampled randomly and studied. For individual PE microfibers, anisotropic diffraction patterns were observed, suggesting chain orientation along the microfiber axial direction. Some microfibers showed the most desired diffraction pattern often found in high‐modulus high‐strength PE fibers. These samples possessed a very high degree of chain orientation along the fiber axis. Owing to a random aggregation of anisotropic microfibers, microfiber aggregates exhibited isotropic diffraction patterns. This work provided further experimental evidence for the proposed nanoextrusion polymerization concept.

2D WAXRD diffraction pattern of a PE microfiber.     

由一种新型非均相聚合方法制备的聚氯乙烯的分子结构

聚氯乙烯(PVC)树脂通常采用自由基本体聚合、悬浮聚合和乳液聚合方法制备.无链转移剂时,头-尾加成和PVC大分子自由基向单体链转移反应分别是链增长和链终止的主要方式,聚合温度成为影响PVC平均分子量及分子量分布的主要因素.     

半连续和间歇式丙烯酸酯三元乳液共聚产物的形态及分子结构研究

研究了半连续和间歇式丙烯酸酯三元乳液共聚产物的形态和分子结构。结果表明,半连续式胶乳粒子呈“多核核壳结构”,其粒径和粒径分布随单体滴加速度减慢而变小。间歇式胶乳粒径较大,粒径分布亦更宽,呈硬相在外的“单核核壳结构”;共聚物分子链中VAc结构单元的序列较长。两种方法所获无规共聚物均存在微相分离结构,分离程度随单体滴加速度的加快而变大。     

原位聚合制备的离子液体/聚合物电解质的研究

采用原位聚合制备出新型的BMIPF6/PMMA聚合物电解质透明弹性膜. 研究结果表明, BMIPF6/PMMA聚合物电解质体系在305 ℃时仍具有较好的热稳定性, 其安全性能优于含有机溶剂的传统非水电解质体系. 随着离子液体含量的增加, 其玻璃化转变温度逐渐减小, 离子电导率升高; 且离子电导率与温度的关系服从VTF方程. 其中, 当BMIPF6的质量分数为50%时, 该聚合物电解质的室温离子电导率高达0.15 mS/cm.