Effect of Polythiophene Content on Thermomechanical Properties of Electroconductive Composites

The thermal, mechanical and electrical properties of polymeric composites combined using polythiophene (PT) dopped by FeCl₃ and polyamide 6 (PA), in the aspect of conductive constructive elements for organic solar cells, depend on the molecular structure and morphology of materials as well as the method of preparing the species. This study was focused on disclosing the impact of the polythiophene content on properties of electrospun fibers. The elements for investigation were prepared using electrospinning applying two substrates. The study revealed the impact of the substrate on the conductive properties of composites. In this study composites exhibited good thermal stability, with T₅ values in the range of 230–268 °C that increased with increasing PT content. The prepared composites exhibited comparable PA T_g values, which indicates their suitability for processing. Instrumental analysis of polymers and composites was carried out using Fourier Transform Infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM).     

Composite Polyamide 6/Polypyrrole Conductive Nanofibers

Conductive Polyamide 6 (PA‐6) nanofibers were prepared by making a conductive polypyrrole coating obtained by a polymerization of pyrrole molecules directly on the fiber surface. A solution of PA‐6 added with ferric chloride in formic acid has been electrospun and the fibers obtained showed an average diameter of 260 nm with a smooth surface. The fibers have been then exposed to pyrrole vapours and a compact coating of polypyrrole was formed on the fiber surface. The growth of the coating was monitored by measuring the increment of the fiber diameter and by FT‐IR spectroscopy. The same technique was used to study the interaction between the ferric chloride and the polyamide chains. The polypyrrole coating on the fibers turned out to be conductive with a pure resistive characteristic and the stability of the conductivity was evaluated in air at room temperature.

     

Novel Cross‐Linked Conducting Polythiophene with Yellow‐Green‐Light‐Emitting Properties and Good Thermal Stability

A novel conjugated polythiophene derivative with polymethacrylate attaching to the polymer backbone via an alkyl spacer was successfully synthesized. A methacrylate‐substituted thiophene monomer, 3‐(hexyl methacrylate)thiophene was prepared and polymerized by free radical polymerization, followed by an electrochemical polymerization. The resulting polymer as a yellow‐green‐light emitter, has potential applications in photoelectronics area.     

Synthesis and Photovoltaic Properties of Polythiophene Incorporating with 3,4-Difluorothiophene Units

Two polythiophene derivatives using fluorine atoms and hexyl or hexyloxy group as electron-withdrawing and donating substituents have been synthesized. The introduction of fluorine atoms to the polythiophene backbones simultaneously lowers the HOMO and narrows the bandgap, and the stronger electron-donating ability of hexyloxy side chain further reduces the bandgap. As a result, poly[3-hexylthiophene-2,5-diyl-alt-3,4-difluorothiophene] （PHTDFT） shows HOMO and bandgap of -5.31/1.83 eV and poly[3,4-dihexyloxythiophene-2,5-diyl-alt-3,4-di- fluorothiophene] （PDHOTDFT） shows HOMO and bandgap of -5.14/1.68 eV, both are lower than --4.76/2.02 eV of P3HT. Benefiting from the lower HOMO, PHTDFT：PC61BM （1 ＂ 1） polymer solar cells obtain a power conversion efficiency of 1.11% and an impressed open-circuit voltage of 0.79 V under solar illumination AM1.5 （100 mW/cm2）.     

Porphyrinated Nanofibers via Copolymerization and Electrospinning

Summary: The first example of the synthesis of acrylonitrile copolymers with porphyrin pendants and the subsequent electrospinning of the resultant copolymers into nanofibers is presented in this communication. Vinyl porphyrin monomers have been synthesized and copolymerized with acrylonitrile through solution polymerization. FT‐IR, NMR, UV‐vis, and fluorescence spectroscopy are used to characterize the copolymers. Preliminary quantum chemical calculations have also been carried out to reveal the activity of the vinyl porphyrin monomers. Nanofibers with a diameter of around 330 nm are prepared by electrospinning the copolymer solutions. Their morphology and porphyrination are clearly observed by field‐emission scanning electron microscopy and fluorescence microscopy. It is speculated that this type of nanofiber may be a latent support of porphyrins for various purposes such as catalysis, molecular imprinting, sensors, and light/energy conversion.

The formation of luminescent nanofibers from porphyrinated polymers.     

CeO2/TiO2复合纳米纤维的制备及光催化性能研究

采用静电纺丝技术和水热合成法制备了CeO₂/TiO₂复合纳米纤维. 利用X射线衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)和比表面积测定(BET)等分析测试手段对样品的形貌及结构进行了表征, 并以罗丹明B的脱色降解为模式反应, 考察了样品的光催化性能. 结果表明: CeO₂纳米粒子均匀地生长在TiO₂纳米纤维表面, 形成了异质结构的CeO₂/TiO₂复合纳米纤维光催化材料. 通过改变碱源, 可以得到不同形貌的CeO₂. CeO₂的存在增加了TiO₂纳米纤维的比表面积, 有效地实现TiO₂光生电子和空穴的分离, 增强了体系的量子效率, 与纯TiO₂纳米纤维相比光催化活性明显提高. 初步探讨了异质结的形成机理.     

聚噻吩/多壁碳纳米管复合材料结构与导电机理的研究

从结构和相互作用方面对聚噻吩(PTh)/多壁碳纳米管(MWNTs)复合材料进行了研究, 结果表明: 一方面聚噻吩本身的结构对其导电性能有一定的影响, 另一方面MWNTs作为一种掺杂剂, 和聚噻吩之间存在强的相互作用, 电子从MWNTs转移到聚噻吩. MWNTs和它周围被掺杂的聚噻吩通过π-π共轭作用形成相对独立的导电单元, 在复合材料的导电体系中起到主要作用, 随着这种导电单元数量的增加直至相互接触, 形成大的导电体系, 复合材料的电导率达到最大值.     

Fabrication of Electrically Conducting Polypyrrole‐Poly(ethylene oxide) Composite Nanofibers

Summary: Electrically conducting polypyrrole‐poly(ethylene oxide) (PPy‐PEO) composite nanofibers are fabricated via a two‐step process. First, FeCl₃‐containing PEO nanofibers are produced by electrospinning. Second, the PEO‐FeCl₃ electrospun fibers are exposed to pyrrole vapor for the synthesis of polypyrrole. The vapor phase polymerization occurs through the diffusion of pyrrole monomer into the nanofibers. The collected non‐woven fiber mat is composed of 96 ± 30 nm diameter PPy‐PEO nanofibers. FT‐IR, XPS, and conductivity measurements confirm polypyrrole synthesis in the nanofiber.

An SEM image of the PPy‐PEO composite nanofibers. The scale bar in the image is 500 nm.     

静电纺纳米复合纤维柔性表面增强拉曼散射传感基底的研究进展

表面增强拉曼散射(Surface enhanced Raman scattering,SERS)是一种分子检测光谱技术,借助SERS基底,可对生物、化学等复杂体系中的痕量分子进行分析。 其中静电纺纳米纤维SERS基底由于具有高比表面积、可透气透水、柔韧可折叠弯曲等特点,在复杂体系中提取、过滤、浓缩痕量分子等应用场景中,其表面结构具有其他刚性SERS基底不可比拟的优势。然而,静电纺纳米纤维SERS基底的发展却受到制备方法的限制,存在检测灵敏度较低、制备过程复杂等问题。 因此,目前的研究工作主要集中在新型制备方法及工艺的开发。 本文综述了静电纺纳米金银复合纤维SERS基底的几种常用制备方法,包括直接混合纺丝法、化学吸附法、静电吸附法、物理沉积法和原位化学还原法,并总结了静电纺纳米纤维SERS基底在复杂体系中提取、过滤、浓缩待测分子的应用,最后对静电纺纳米复合纤维SERS基底的发展进行了展望。     

Synthesis of poly(o‐phenylenediamine) nanofiber with novel structure and properties

The poly(o‐phenylenediamine) (PoPD) was synthesized from the monomer o‐phenylenediamine in various organic solvent medium viz. dimethyl sulfoxide (DMSO), N,N‐dimethyl formamide (DMF) and methanol using ammonium per sulfate as a radical initiator. The structure just like polyaniline derivative with free ?NH functional groups of the synthesized polymers confirmed by various standard characterizations was explained from the proposed polymerization mechanism. All the synthesized polymers were completely soluble in common organic solvent like DMSO and DMF because of the presence of polar free ?NH functional groups in its structure. The formation of polymer nanofiber by reverse salting‐out process was confirmed, and the synthesized polymer in DMSO medium was the best polymer in terms of nano‐morphology as well as conducting properties. Interestingly, the average DC conductivity of undoped polymer film was recorded as 2.21 × 10^?6 Scm^?1 because of induced doping through self charge separation. Moreover, the conductivity of the polymer film was further increased to 1.16 × 10^?3 Scm^?1 after doping by sulfuric acid. Copyright © 2016 John Wiley & Sons, Ltd.     

Fe-Co-Ni合金纳米粒子镶嵌的碳纳米纤维的简单制备及其吸波性能

通过在氩气中碳化含有乙酰丙酮金属盐的电纺聚丙烯腈纳米纤维合成了镶嵌（Fe_1-xCo_x）_0.8Ni_0.2（x=0.25,0.50,0.75）合金纳米粒子的碳纳米纤维,用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、振动样品磁强计（VSM）和矢量网络分析仪（VNA）等对其物相、形貌、微观结构、静磁及电磁特性进行表征和分析,并根据传输线理论模拟计算了2~18 GHz频率范围内的微波吸收性能。结果表明：所制备的复合纳米纤维具有典型的铁磁特征,由无定形碳、石墨和面心立方结构Fe-Co-Ni合金三相组成,原位形成的合金纳米粒子沿纤维轴向均匀分布,且被有序石墨层所包覆。磁损耗和介电损耗间的协同作用及特殊的核/壳微观结构使仅含5%（w/w）的（Fe_1-xCo_x）_0.8Ni_0.2/C复合纳米纤维的硅胶基吸波涂层表现出优异的微波吸收性能。当涂层厚度为1.1~5.0 mm时,x=0.25、0.50和0.75的样品最小反射损耗分别达到-78.5、-80.2和-63.4 dB,反射损耗在-20 dB以下的吸收带宽分别为14.9、14.8和14.5 GHz,几乎覆盖整个S波段至Ku波段。通过调节合金的组成可对材料的电磁特性及微波吸收性能进行一定程度的控制。     

Electrospun Highly Ordered Mesoporous Silica–Carbon Composite Nanofibers for Rapid Extraction and Prefractionation of Endogenous Peptides

A simple method was developed for the preparation of ordered mesoporous silica–carbon composite nanofibers (OMSCFs). The OMSCFs exhibited high carbon content, continuously long fibrous properties, uniform accessible mesopores, and a large surface area. The OMSCFs were also found to have ion‐exchange capacity. On the basis of the size‐exclusion effect of the mesopores and mixed‐mode hydrophobic/ion‐exchange interactions, the OMSCFs were applied for rapid enrichment of endogenous peptides by using a miniaturized solid‐phase extraction format. The adsorption mechanism was studied, and the eluting solution was optimized with standard peptide/protein solutions and protein digests. Employing a successive three‐step elution strategy, followed by LC‐MS/MS analysis, led to excellent performance with this approach in the extraction and prefractionation of peptides from human serum.     

Dry Spinning Based Spinneret Based Tunable Engineered Parameters (STEP) Technique for Controlled and Aligned Deposition of Polymeric Nanofibers

Polymeric nanofibers are finding increasing number of applications and hold the potential to revolutionize diverse fields such as tissue engineering, smart textiles, sensors, and actuators. Aligning and producing high aspect ratio fiber arrays (length/diameter > 2 000) in the sub‐micron and nanoscale diameters has been challenging due to fragility of polymeric materials, thus making it difficult to deposit them as one dimensional structures functionally interfaced with other systems. Here, we present a pseudo dry spinning technique which allows precise control on fiber diameters and further allows deposition of fiber arrays in aligned configurations. Control on fiber diameters ranging from 50–500 nm and having lengths of several millimeters is achieved by altering the polymeric solution concentration. In the dilute and semi‐dilute unentangled concentration domain droplets or beaded fibers are observed to form. Smooth uniform diameter fibers are observed to form at the onset of semi‐dilute entangled concentration regime. For a given molecular weight, the increase in fiber diameter with increasing solution concentration is attributed to both the increase in the entanglement density and the decrease in the radius of gyration of solvated polymer molecules. Using this technique polymeric fiber arrays in single and multiple layers are demonstrated which can be used towards developing strong textiles, biological scaffolds, and sensor networks.

     

含石墨烯的聚乳酸复合纳米纤维的制备及细胞相容性

利用电纺丝技术制备了聚乳酸(PLLA)-石墨烯(Gr)复合纳米纤维.通过SEM、TEM及拉曼光谱观察和分析了该复合纳米纤维的形貌及Gr在PLLA中的分散状态,通过DSC、TG、力学拉伸及接触角测试等表征方法研究了PLLA-Gr复合纳米纤维的热性能、力学性能、亲水性等物理性能,最后,通过MTT法检测一种神经胶质细胞——雪旺细胞(SCs)在该复合纳米纤维支架上的生长和增殖行为,评价其细胞相容性.结果表明:低含量的Gr能较好地分散在PLLA纳米纤维中,且随着m(Gr)∶m(PLLA)从0增加到2.0％,所得到的纤维直径呈现先减小后增加的趋势.当m(Gr)∶m(PLLA)增加到1.0％时,PLLA Gr纳米纤维的直径达到最小,为(0.50±0.19) μm,对应的拉伸强度较未添加Gr时增加也最大达50％.PLLA-Gr纳米纤维膜的结晶度与Gr的含量和分散性有关.细胞培养1、4、7d后的MTT检测结果表明PLLA-Gr复合纳米纤维能促进SCs的黏附和生长.PLLA-Gr复合纳米纤维具有较好的细胞相容性.     

热处理对富氮碳纳米纤维结构及储锂性能的影响

以聚丙烯腈(PAN)为原料,经静电纺丝、稳定化和碳化,制备了碳纳米纤维(CNFs)。系统地研究了氮的种类及含量对锂离子电池(LIBs)中Li+的储存性能和负极容量的影响。碳化过程中纤维从无定形碳向石墨化碳结构转变,含氮官能团减少,结构的变化对Li+在CNFs电极中的存储位置有很大的影响。结果表明,Li+不仅可以存储在石墨化碳层之间,还可以存储在氮功能化引起的缺陷部位,后者主要是由于碳材料的氮掺杂而使LIBs的电化学性能改善。碳化温度为600℃时,可以产生足够高的氮含量,从而提高电极的容量。在电流密度为0.1 A·g^-1时,循环200次之后比容量高达560 mAh·g^-1,即使在1 A·g^-1的高电流密度下,循环1000次比电容量仍然保持在200 mAh·g^-1。     

导电聚合物电致变色材料*

由于在电致变色、显示、军事等领域的广泛应用,电致变色材料受到了人们越来越多的关注。本文综述了聚苯胺(PANI)类、聚噻吩(PTh)类、聚吡咯(PPy)类及复合导电聚合物电致变色材料的性能及其研究进展,同时简单地叙述了这些材料作为电致变色材料的应用前景,指出具有丰富颜色变化、良好的稳定性及成膜性的共聚物及有机/无机复合导电聚合物材料是未来电致变色材料发展的方向。     

电纺法及其在制备聚合物纳米纤维中的应用

在介绍电纺法的基础上,对电纺法制备聚合物和导电聚合物纳米纤维的影响参数和电纺纤维的应用研究进行了综述,同时展望了该方法在制备聚合物纳米纤维方面存在的挑战和机遇。     

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...